Take the 2020 charitable deduction for non-itemizers above the line

[MaxGhenis]

Sol reviews r1 to r4 addressed; Sol delta review r5 pending. Marked ready so CI runs the full suite (the host's heavy lock is reserved until 2026-10-21).

Summary

For taxable years beginning in 2020 only, CARES Act § 2204 added 26 U.S.C. § 62(a)(22) and § 62(f). They let an individual who does not itemize deduct up to $300 of cash gifts to § 170(b)(1)(A) organizations in arriving at AGI (2020 Form 1040 line 10b). The model took it below the line, with the 2021 § 170(p) deduction, so 2020 AGI was too high for non-itemizing donors. That fed through every AGI-based test, every MAGI built from the above-the-line list, and every state that starts from federal AGI.

This PR also fixes a related bug. Since 1d42fc4 (#5973), charitable_deduction no longer nets out the non-itemizer amount, but gov.irs.deductions.itemized_deductions still listed charitable_deduction_for_non_itemizers for 2020–2021. So itemizers counted up to $300 (2020) or $300/$600 (2021) of cash gifts twice. The double count also reached the state itemized deductions built on itemized_deductions_less_salt or total_itemized_taxable_income_deductions (DC, IA, ID, KS, KY, MD, ME, MN, MS, NE, NM, OK, OR, VA, the WI credit).

Law (verified against the primary sources)

• P.L. 116-136 § 2204 (file p.65) adds § 62(a)(22), "the amount (not to exceed $300) of qualified charitable contributions made by an eligible individual". It also adds § 62(f): (1) an eligible individual does not elect to itemize; (2) gifts must be cash to a § 170(b)(1)(A) organization, not to a § 509(a)(3) organization or a donor-advised fund, and carryovers are excluded.
• P.L. 116-260 div. EE § 212 (file pp.1888–1889):
  • (a) adds § 170(p) for 2021 ($300, $600 joint);
  • (b) adds § 63(b)(4), taking it from AGI;
  • (c) strikes § 62(a)(22) and (f) for years after 2020.
• 2020 Form 1040: line 10c = 10a + 10b; line 11 = 9 − 10c. The 2020 instructions:
  • line 10b (p.30);
  • Social Security Benefits Worksheet line 6 (p.31), IRA Deduction Worksheet line 4 (p.94), Student Loan Interest Worksheet line 3 (p.96): each subtracts line 10b;
  • Unemployment Compensation Exclusion Worksheet line 5 (p.88): subtracts 10c;
  • 2020 Pub. 970 Worksheet 6-1 line 2 (tuition and fees MAGI) also subtracts line 10b.
• The $300 cap applies to every return, married filing separately included. The 2020 instructions give "$150 if married filing separately", but § 62(a)(22) and (f) have no separate-return rule. Under PolicyEngine's statute-first rule (Max, 2026-10-19: the statute governs where it conflicts with forms, instructions or practice), the model follows the statute. A joint return keeps $300 per return, the reading that P.L. 116-260's explicit "$600 in the case of a joint return" for 2021 implies.
• 2021 Form 1040: line 12b is below AGI (2021 instructions p.32).

Changes

Federal

• charitable_contributions_ald (TaxUnit, 2020 block of gov.irs.ald.deductions): ~tax_unit_itemizes × min(head's and spouse's cash to 170(b)(1)(A) organizations, $300). The cap is gov.irs.ald.charitable_contributions.cap, $300 in 2020 and 0 otherwise. It uses resolved_charitable_cash_donations_50_pct from Model full 5-tier charitable deduction limits under IRC § 170(b) #10192, summed with tax_unit_non_dep_add, so a dependent's gifts stay on the dependent's own return. It returns 0 in years that don't list it.

• charitable_contributions_ald_person: each filer's part, in proportion to their own gifts. above_the_line_deductions_person (Give each spouse their own above-the-line deductions in per-person AGI #9890) attributes the deduction by it.

• Itemization choice. In 2020 AGI depends on the choice, so tax_unit_itemizes takes:

  • everything the itemizing branch deducts from AGI: Schedule A, wagering losses, and the QBI deduction it allows;
  • everything the not_itemizing branch deducts from AGI, plus what not itemizing takes off AGI (line 10b and its knock-ons, such as taxable Social Security).

  That makes the deduction comparison choose the lower taxable income. It matters without branching, which is how CI runs the YAML tests (update_itemization.sh), and in the tie fallback. A main-sim computation would be a cycle: AGI → ALD → choice → itemized deductions, and standard_deduction → bonus_guaranteed_deduction → AGI.

• get_itemization_branch (tools/general.py) gives all three callers the same branch. Model the claim of right repayment deduction and credit (26 U.S.C. 1341) and North Carolina's rules that depend on it #10038 adds the same helper with a claim-of-right override; whichever lands second keeps Model the claim of right repayment deduction and credit (26 U.S.C. 1341) and North Carolina's rules that depend on it #10038's version.

• non_itemizers_amount (§ 170(p)) is 0 in 2020. charitable_deduction_for_non_itemizers is no longer in the 2020–2021 itemized list.

• The tuition and fees MAGI subtracts line 10b. Every MAGI that iterates the above-the-line list now subtracts it too, as the 2020 worksheets require: SS, UC, IRA, student loan, person and Medicaid AGI.

States (2020): each line was verified from the state's own 2020 source.

State	Treatment	Source
CA	add back (ca_additions)	2020 Schedule CA (540) instructions, Part I, Section C, line 22 col. B (p.48)
IN	add back (in_add_backs)	IC 6-3-1-3.5(a)(26), Information Bulletin 119 (p.2)
KY	add back each filer's part (ky_additions)	2020 740 instructions, Schedule M line 5 (p.27)
MN	add back (2020 additions.sources block); AMT income adds it back; the SS worksheet step 8 leaves it out	M1NC line 6; M1MT line 4; M1M p.8 step 8
NC	add back (nc_additions)	2020 D-400 Schedule S, Part A, line 16
NY, NYC	New ny_recomputed_federal_agi (IT-201 line 19a = federal AGI + IT-558 A-003). Read by: NY AGI; the IT-196 floors and limitation; the NY household, Empire State child, child care and real property tax credits; the disability exclusion; the NYC household, school, child care and tax-elimination credits. get_ny_recomputed_branch sets federal AGI to line 19a and keeps the federal itemization choice; for the Empire State child credit it also keeps the federal tax and EITC as reported. From it, the NY and NYC EITC take the federal credit recomputed with line 19a (IT-215), and the child credit takes its pre-TCJA federal credit (IT-213 Worksheet A keeps Form 1040 line 18 as reported; Worksheet C line 7 carries Schedule 8812 line 13, which uses the EITC as reported)	IT-201-I p.16–17, IT-558 A-003, IT-196 lines 2/17/26, IT-213-I p.2, IT-214, IT-215-I p.2, IT-216 line 9, IT-221
MA	disallowed in Part B AGI	TIR 20-9, B(6)
AZ	subtracted from the 25% charitable standard deduction increase	2020 Form 140 worksheet line 5C (p.25)
MI	off total household resources	Michigan Treasury FAQ; 2020 book p.28

Other states that start from federal AGI conformed. In CA, IN, KY, MN and NC, an audit of every other 2020 reader of federal AGI found that each uses federal AGI as reported (line 11) and so needs no change. The exceptions are fixed here: CA's CVRP counts income before adjustments, and MN's AMT and Social Security worksheet differ as above (Minnesota's retroactive Laws 2023, ch. 1, sec. 22). The audit is at ~/reviews/charitable-ald-2020/state-agi-readers.md. The research table is at ~/reviews/charitable-ald-2020/state-conformity.md; rows inferred from conformity dates are labelled.

Follow-ups (not in this PR; chips):

• South Carolina rejected both the 2020 and 2021 deductions (starts from federal taxable income, unchanged here).
• OR/WI/MT itemized coordination and Iowa's equivalent deduction.
• A 2021 § 170(p) state audit.
• MN 2017–2020 SS constants are backdated from 2021.
• Schedule A and § 170(p) still count dependents' gifts.

Invariants (tests/core/test_charitable_contributions_ald_invariants.py)

1. The deduction is min(filers' cash, $300) for a non-itemizer, 0 for an itemizer, and 0 in 2021. Dependents' gifts are excluded.
2. AGI equals gross income less the above-the-line deductions, which include it.
3. No gift is deducted twice: Schedule A totals equal their components, in 2020 and 2021.
4. Differential check: the simulation's income tax equals that of the chosen branch, and that is the lower of the two.
5. CA adds it back, NY's line 19a adds it back, and MA Part B AGI keeps it.
6. Without branching, the choice leaves the lower taxable income of the two branches. A seeded population includes New Hampshire households at the margin. Dropping the AGI reduction from the comparison makes this test fail (mutation-checked).

The tests use a seeded population and Hypothesis draws. Cost: 3 tests, 24.8 s, 2.65 GB peak RSS (local macOS, not a CI measurement).

Tests

• charitable_contributions_ald.yaml: 12 cases, including $300 MFS and gifts to non-170(b)(1)(A) organizations.
• integration.yaml: 14 cases worked line by line from the 2020 Form 1040:
  • AGI and tax for single, joint and MFS filers;
  • an itemizer counted once;
  • the choice the deduction flips, with and without branching, including wagering losses and a QBI deduction that differs between the choices;
  • the Social Security and UC exclusion worksheets;
  • a dependent's gifts;
  • the tuition MAGI;
  • 2021 itemizer and non-itemizer.
• State cases in ny_eitc, nyc_eitc, ny_ctc_pre_2024, the NYC household, school and child care credits, ca_additions, in_add_backs, ky_additions, mn_additions, mn_amt_taxable_income, mn_social_security_subtraction (2020 worksheet constants inline), nc_additions, ny_recomputed_federal_agi, ma_part_b_agi, the AZ increase, and mi_household_resources.
• Fails on main: at the first round, 8 of 9 integration cases failed on main on substance. Sol r1 reproduced each new case's failure before the fix.
• Local runs: every changed YAML file passes, one file at a time. A local sweep of every 2020 file at the r1 head passed (194 files, 2,086 cases); the sweep at this head was withdrawn from the reserved heavy queue in favour of CI. The Python ALD tests pass, run one file at a time at e4d51ea: 32 tests across the new invariants, spouse and dependent ALD invariants (including the attribution audit), ALD determinism and Michigan line 30.

Impact

No change to any year with records in the default dataset (2020 and 2021 microsimulations read every input as zero). Household examples:

• A 2020 single non-itemizer with $40,000 of wages and $500 of gifts: AGI $39,700 (was $40,000), taxable income unchanged.
• A 2020 MFS filer: $300 instead of $150.
• A 2021 itemizer with $500 of gifts: $500 on Schedule A (was $800).

Coordination

• itemized_deductions.yaml: Add North Carolina's wagering losses itemized deduction from 2025 (G.S. 105-153.5(a)(2)e) #10110, Count gambling winnings in federal gross income and fix the wagering losses deduction #10070, Model the claim of right repayment deduction and credit (26 U.S.C. 1341) and North Carolina's rules that depend on it #10038 and the claim-of-right states each add an item to all three blocks, which this PR collapses into one. Whichever lands second keeps one block plus the new items.
• tax_unit_itemizes.py and tools/general.py: Model the claim of right repayment deduction and credit (26 U.S.C. 1341) and North Carolina's rules that depend on it #10038 adds the same get_itemization_branch; keep its claim-of-right version.

axiom: TheAxiomFoundation/rulespec-us#1725 queued (§ 62(a)(22)/(f) for 2020 with the $300 cap for every return, and the 2021 version of § 170(p); blocked on corpus ingest TheAxiomFoundation/axiom-corpus#843)

🤖 Generated with Claude Code

CI repair (2026-10-20): Merged current main (bda23eac4c) and reproduced the exact three-row failure with CI's branching-disabled setting. Main's comparison omitted the non-itemizer charitable deduction; removing its erroneous duplicate from Schedule A exposed this related bug. For rows 65–67, deductions of $12,699/$12,701/$12,800 beat the $12,550 standard deduction alone but lose to $12,850 including the $300 cash deduction, causing $33.22/$32.78/$11.00 excess tax. The model comparison now counts the capped charitable deduction, including the 2026 limitation path and equal-tax fallback. The invariant and its tolerances remain intact.

Validation: 32 ALD Python tests and the repair YAML's 12 cases passed locally, one file per foreground process; make format passed. CI confirmed all 32 ALD Python tests and all 213 cases in the full PR's 22 changed YAML files. The formerly failing Rest job is green; further Contrib checks remain in progress.

[MaxGhenis]

Handing this PR to the US + core hub.

• Head: 93d6899ead. It is upstream/main merged into the reviewed head 14a8d24d27; main had moved with the military retirement PR Wire military retirement pay and survivors into federal and state tax (#10181) #10182. The one conflict was mn_amt_taxable_income.yaml, where both sides had appended a case; both are kept, and the file passes (6 cases). mn_amt_taxable_income.py merged cleanly and now has both main's military pension subtraction and this PR's charitable add-back.
• Review: GPT-6.1 Sol r5 APPROVE at 14a8d24d27 (~/reviews/charitable-ald-2020/review-5.md). The findings from r1–r4 were all fixed, and each fix was verified by the next round (review-1.md … review-4.md; evidence in review-N-evidence/).
• Passed locally:
  • every changed YAML file;
  • all 204 NY, NYC, MN and KY tax YAML files (1,423 cases);
  • a sweep of every YAML file with a 2020 case at the r1 head (194 files, 2,086 cases);
  • the ALD Python tests (32, including the new property tests and Give each spouse their own above-the-line deductions in per-person AGI #9890's attribution audit);
  • an NYC end-to-end probe with branching on and off.
• Pending: CI at 93d6899ead. On e4d51eac02, before later pushes cancelled the run, the PR validation, packaging, Household API Partners and Quick Feedback checks passed. The host heavy queue is reserved (Route A), so CI is the full-suite run.
• Depends on: nothing.
• Coordination:
  • Model the claim of right repayment deduction and credit (26 U.S.C. 1341) and North Carolina's rules that depend on it #10038 adds the same get_itemization_branch (tools/general.py) with a claim-of-right override; keep Model the claim of right repayment deduction and credit (26 U.S.C. 1341) and North Carolina's rules that depend on it #10038's version.
  • itemized_deductions.yaml: this PR collapses the 2018/2020/2022 blocks into one, and Add North Carolina's wagering losses itemized deduction from 2025 (G.S. 105-153.5(a)(2)e) #10110, Count gambling winnings in federal gross income and fix the wagering losses deduction #10070, Model the claim of right repayment deduction and credit (26 U.S.C. 1341) and North Carolina's rules that depend on it #10038 and the claim-of-right state PRs each add an item to all three. Whichever lands second keeps one block plus the new items.
• Decisions: none queued. The MFS cap follows Max's 2026-10-19 statute-first ruling (d1461 et al.): $300 per § 62(a)(22), against the instructions' $150. Per HUB-PROTOCOL, the source-conflict register should record this after merge.
• Axiom: Encode 26 U.S.C. 62(a)(22) and 62(f) for 2020 and the 2021 version of 170(p) (PE-US #10186 parity) TheAxiomFoundation/rulespec-us#1725 queued, blocked on Ingest P.L. 116-136 (CARES Act) and P.L. 116-260 (CAA 2021) for the 2020 and 2021 non-itemizer charitable deductions TheAxiomFoundation/axiom-corpus#843.
• Follow-ups: nine chips are spawned in session local_036bf9f1: SC; OR/WI/MT/IA; the 2021 § 170(p) state audit; the no-branch comparison in 2021/2026; MN SS constants; dependents' gifts on Schedule A/§ 170(p); § 86(b)(2)(A) sections 222/199; IN/NC/KY/MN/CA 2020 values; the NYC EITC 2020 rate.

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