We now know Republican senators’ plan to repeal and replace Obamacare. And while GOP senators are struggling with the question of whether they can pass the bill, they’ll also be asking a longer-term question: Will Americans like what’s in it? In general, public opinion toward the GOP’s health reform efforts has been decidedly negative. But the key question is not necessarily how the bill polls in the coming weeks — it’s what Americans will think about the legislation if it passes and they begin to experience changes to their health insurance.

One way to assess Americans’ likely views about the GOP’s Better Care Reconciliation Act is to look at what they do and don’t like about the Affordable Care Act. In a recent interview with Vox, Alaska Sen. Lisa Murkowski — a pivotal vote on health care— summarized her constituents’ views like this: “I continue to hear stories of great frustration. Increasing premium costs. Increasing share of deductibles. Decreasing access. They know what they don’t like. They know what they do like. They do like the fact that they have gotten coverage for pre-existing conditions.”

For years, the Kaiser Family Foundation has surveyed Americans about health policy and the ACA, aka Obamacare. Periodically, those surveys have included open-ended questions about why Americans do or don’t support the law. Since the implementation of the law’s main features in 2014, Americans have thought about the ACA much as the Alaskans described by Murkowski have: Those who back it cite increased access, and those who oppose it worry about rising personal costs.

Consider the tables below, in which I categorized responses along with the share of people falling into each category in Kaiser’s March 2014 and March 2015 surveys. For the law’s opponents, the single biggest issue to emerge from these answers is what I term “personal cost.” Thirteen percent of all respondents — and 23 percent of the law’s detractors — gave responses that fit into this category. This March 2014 response was emblematic: “My insurance has went up 400 percent. I think it rips off the doctors and young people. I can’t believe Congress will pass a law with them not knowing what it’s about.” If the new Senate bill seeks to improve upon the ACA in the public’s eyes, and especially in the eyes of the ACA’s detractors, it will need to keep out-of-pocket health care costs down.

Reasons survey respondents gave for opposing the ACA REASON SHARE OF RESPONDENTS Personal costs/unaffordable 12.8% – Infringes on rights/unconstitutional 8.2 – General negative 7.3 – Not proper role of government 5.7 – Constrains choice 4.0 – Unfair 4.0 – ACA is too complicated 3.4 – Costs government too much 1.7 – Economic costs 1.6 – Bad for specific groups 1.6 – Government won’t do this well 1.4 – Policymaking processes 1.3 – Hurts quality of health care 0.7 – Don’t want illegal immigrants included 0.3 – Concerned law will fund abortion 0.3 – Prefers single-payer system 0.3 – Leaders oppose ACA 0.2 – From Kaiser Family Foundation surveys in March 2014 and March 2015 Source: Kaiser Family Foundation

Reasons survey respondents gave for supporting the ACA REASON SHARE OF RESPONDENTS Increased access 16.9% – Fairness and equality 9.1 – Good for U.S. 5.6 – Affordability/lowers costs 5.3 – Step in right direction 2.5 – Protecting consumers 1.7 – Helps specific groups 1.6 – Reform is overdue 1.0 – Positive international comparison 0.6 – Improves quality of health care 0.2 – Leaders support ACA 0.2 – Balances federal budget 0.1 – Economic benefits 0.1 – From Kaiser Family Foundation surveys in March 2014 and March 2015 Source: Kaiser Family Foundation

There is also significant opposition to the ACA as a matter of ideology. Eight percent of all respondents were opposed because they felt its requirement that most people buy insurance was an infringement of personal rights. For instance, one respondent explained that it should be “completely up to people if they want to do it or not; people shouldn’t be forced to get health insurance.” Another 6 percent raised closely related concerns about health insurance being outside the proper scope of government.

People were less concerned, in the end, about the effect the ACA had on the budget deficit, or the federal government’s long-term spending. It wasn’t always that way, though. In three surveys conducted after the law was enacted but before it was implemented, the most prevalent concern among opponents was that the law would drive up spending and so increase taxes, the deficit, or both. But after implementation, those concerned dropped to just 1.7 percent of responses, perhaps partly because the law’s main taxes don’t hit many voters directly. While one of the new GOP bill’s main features is its large tax cuts for high-income Americans, the ACA’s taxes haven’t been a cause for much concern in years.

Among the public, ACA opposition stems more from concerns about rising personal costs than costs borne by the government. One might think that the GOP’s activist core has different priorities, priorities more closely aligned with the Senate GOP’s bill. To find out, I teamed up with Georgetown’s Hans Noel and Huffington Post’s Pollster and fielded a separate poll of 1,000 Republican and Democratic activists in October 2016 via YouGov that can speak to that question. It turns out that activists who oppose the ACA don’t differ as much from the public as might be expected. They, too, prioritize reducing personal costs — 23 percent of all responses talked about rising costs under the ACA. By contrast, just 7 percent of all activists’ responses fell into the more ideological category about the ACA being an improper exercise of federal authority. So if the GOP bill doesn’t focus on reducing costs, it won’t just be out of sync with GOP-leaning citizens–it will be out of sync with the GOP’s activists, too.

With respect to ACA supporters, too, Murkowski’s perceptions are on target. The most common reason respondents gave in 2014 and 2015 for supporting the ACA was increased access: 17 percent of all respondents and 37 percent of all the law’s backers cited increased access to health care. One supporter, for instance, backed the law because “everyone can have health insurance … I went several years and haven’t had it and know how difficult it is to go to the doctor/hospital.” Meanwhile, another 9 percent of respondents fell into a related category focusing on fairness and people’s right to health care.

The ACA stands as a reminder to politicians that if you want a law to hold up, you have to think about its political dimensions as well as its policy dimensions. Americans have come to think about the ACA largely in terms of their personal health care costs and access to the system. Whatever the Republicans ultimately come up with is likely to be judged using similar criteria. And given his remarks Thursday on Fox News, Health and Human Services Secretary Tom Price knows it: He argued for the legislation by saying, “We’ve got prices going up, we’ve got deductibles going up, premiums going up. … We’ve got people who have an insurance card but they don’t have any care because they can’t afford the deductible.”

Still, initial analyses suggest that the proposed changes probably won’t cut out-of-pocket spending. If those prove accurate, and if the reform reduces access to health insurance, it’s hard to envision the bill becoming more popular than the law it seeks to replace.

Tiger Brown, Saleel Huprikar, and Louis Lin provided research assistance. A Russell Sage Foundation Presidential Authority Award supports Dan Hopkins’s ACA-related research.