Recent Legislative Changes to Substitution: 2023-2025 Updates

The way amendments are swapped out in the U.S. Congress has changed more in the last two years than it has in the past two decades. If you’ve ever watched a committee markup on C-SPAN and wondered why some changes get blocked while others rush through, the answer now lies in a set of technical, high-stakes rules that took effect in early 2025. These aren’t just procedural tweaks-they’ve reshaped who gets to shape the law, and how fast.

What Exactly Is Amendment Substitution?

Amendment substitution is when a lawmaker replaces the entire text of one proposed change to a bill with a new version. Before 2023, any member could drop in a new amendment at the last minute, even if it completely rewrote the original intent of the bill. That’s how you got things like a climate bill suddenly containing a provision about offshore drilling-just slipped in during a quiet afternoon markup. The old system was chaotic. The new one? It’s structured, strict, and heavily controlled.

The biggest shift came with H.Res. 5, adopted on January 3, 2025, which became the standing rulebook for the 119th Congress. This wasn’t just a minor update. It eliminated the automatic right to substitute amendments that had existed since 2007. Now, you can’t just swap out language on the floor. You have to file it 24 hours in advance, through a digital portal called the Amendment Exchange Portal, which went live on January 15, 2025.

The New Rules: How It Works Now

Here’s how substitution works today, step by step:

1. You draft your replacement amendment and upload it to the Amendment Exchange Portal at least 24 hours before the committee meeting.
2. The system requires you to tag every line you’re changing with exact line numbers from the original text.
3. You must explain why you’re making the change and declare whether it’s a “germane modification”-meaning it stays within the scope of the bill.
4. Each committee now has a five-member Substitution Review Committee: three from the majority party, two from the minority. They have 12 hours to approve or reject your submission.
5. Your change gets classified as Level 1, 2, or 3 based on how much it alters the bill’s substance.

Level 1? Minor wording fixes. Easy approval. Level 2? Procedural shifts, like changing deadlines or reporting requirements. Usually okay. Level 3? That’s the big one-changing policy, adding new programs, removing funding. These need 75% committee approval. That’s up from 50% before. In practice, that means majority party members now control nearly all major changes.

Why the Change? Efficiency vs. Fairness

House Republican leadership, led by Rules Committee Chairman Michael Johnson, argued the old system was broken. “We were drowning in poison pill amendments,” Johnson said in January 2025 testimony. “Legislators couldn’t even read the bills before voting.” The numbers back that up. In the first quarter of 2025, amendment processing time dropped by 37%. The number of bills passing committee markup jumped 28%.

But for minority party members, the system feels rigged. In the same period, minority members filed 58% more formal objections to rejected substitutions. Representative Pramila Jayapal (D-WA) had her amendment to H.R. 1526 rejected because the portal misclassified her changes as Level 3. She argued it was a procedural tweak-Level 2. The system said otherwise. No appeal. No debate.

Staff surveys show the divide clearly. A May 2025 survey of 127 committee staffers found 68% of majority party staff called the system “more efficient.” Meanwhile, 83% of minority staff said it “restricts legitimate input.”

Senate vs. House: A Tale of Two Chambers

The Senate hasn’t changed its rules. There, you still just need to give 24 hours’ notice. No review committee. No severity levels. No portal. Substitutions move faster-43% faster, according to the Congressional Management Foundation. That’s created a weird imbalance. A bill might pass the House with tight controls, then get gutted or expanded in the Senate with a single amendment swap. It’s one reason why so many bills die in conference committee.

Some lawmakers are pushing to fix that. A July 2025 draft of a Senate GOP megabill tried to standardize substitution rules across both chambers. But the Senate parliamentarian shot down key parts, ruling they violated the Byrd Rule-meaning they couldn’t be included in budget reconciliation bills. So the mismatch stays.

Real-World Impact: What’s Changed on the Ground

The new rules have rewritten how lobbying works. Firms that used to focus on floor votes now spend more time cultivating relationships with committee staff who control the substitution portal. Lobbying spending on committee-specific efforts rose 29% in the first half of 2025, according to Quinn Gillespie & Associates.

Disaster response has suffered. In May 2025, 67% of emergency relief amendments required special rule waivers because the 24-hour filing window made it impossible to respond to sudden crises. Congress had to pass temporary exceptions just to get aid to flood victims in Louisiana and wildfire survivors in California.

And there are still glitches. In January 2025, 43% of first-time filers messed up the metadata requirements. Training helped. By May, the error rate dropped to 17%. But the ambiguity around Level 3 classifications remains. Minority staff say it’s used selectively. Majority staff say it’s objective. The truth? It’s both.

What’s Next?

There’s already a bill in motion: H.R. 4492, the Substitution Transparency Act. Introduced in June 2025, it would require all Substitution Review Committee decisions to be made public within 72 hours. That could reduce partisan bias-but it could also open the door to political pressure.

Legal challenges are brewing. The Constitutional Accountability Center filed an amicus brief in May 2025 arguing the rules violate the First Amendment by restricting members’ ability to propose amendments. Others say it violates the Presentment Clause of the Constitution, which requires bills to be passed by both chambers before becoming law. Those arguments are still being weighed.

Long-term, experts are split. The Heritage Foundation says these changes are here to stay-“permanent entrenchment of efficiency.” The Brennan Center warns of a backlash. “After the 2026 elections,” they wrote, “voters may demand a return to open debate.”

What This Means for You

If you’re a citizen following legislation, you’ll notice bills moving faster-but with less visible debate. The changes make it harder to track how a bill evolved. You can’t just read the floor speeches anymore. You have to dig into the Amendment Exchange Portal records, which are now public but buried in technical metadata.

If you’re a policy advocate, your job just got harder. You can’t rely on last-minute amendments to fix a bill. You need to plan weeks ahead. Build relationships with committee staff. Understand the Level system. Know the portal inside and out.

And if you’re a student of democracy? This is a real-time experiment in power. The system is more efficient. It’s also less open. The question isn’t whether it works better-it’s whether it works fairly.