In terms of ideology, it’s fascinating how sorted out the two political parties have become. The days of conservative-leaning Democrats having a strong and moderating voice in their party, just as liberal-leaning Republicans used to have in theirs, are long gone. This has effectively pushed the Democratic Party to the left and the Republican Party to the right. It hasn’t just happened in Congress; it’s happened among the rank-and-file party members as well.

Many partisans have come to assume that everyone sees things exactly the way they do, leaving little tolerance for diversity of views. As a result, party bases can become out of sync with independents—the large chunk of voters in the middle that often decides who wins hotly contested general elections. So primary-election politics is often very different from general-election politics, particularly in competitive states and districts. Those in safe seats can afford to see the world far differently than those who have to worry about swing voters.

That dynamic is particularly clear on health care, one of the most politically litigated issues of our time. Democrats had a problem of groupthink during much of the Obama years, assuming that independents saw the need for comprehensive health care reform in the same way that liberals did. Republicans then made the same mistake, assuming that everyone else hated Obamacare as much as conservatives did. Republicans have now shifted to the point where they are very much out of sync with independent voters.

The most authoritative polling on health care is from the nonpartisan Kaiser Family Foundation, which has tracked public opinion on the issue since long before the Affordable Care Act passed. Pollsters in both parties highly respect the Kaiser data.

Since March of 2010, just days after Obamacare was signed into law, the Kaiser pollsters have been asking national samples of Americans their view of the law almost monthly. In July of 2010, for example, 50 percent viewed the ACA favorably, 35 percent unfavorably. But by January 2011, those numbers had effectively flipped, with 41 percent having a favorable view and 50 percent viewing it unfavorably. It was a roller-coaster for years after that, with unfavorable usually running well ahead of favorable; in July of 2014, unfavorable hit a high of 53 percent. But since the departure of President Obama and the arrival of President Trump, the ACA’s favorable ratings have been on the rise. In the most recent, Feb. 15-20 Kaiser poll of 1,193 adults (1,004 registered voters), 54 percent viewed the law favorably, up 4 points from January, and 42 percent viewed it unfavorably in both months.

Many Americans had doubts about Obamacare, viewing it as a flawed program, but came to see its benefits once Republicans controlled the White House as well as the House and the Senate and the program was suddenly endangered.

What is really interesting—and explains how Congress has behaved—is how different the perception of the program is among those who identify with each party. In the new poll, just 19 percent of those who identify as Republicans had a favorable view of the ACA and 78 percent had an unfavorable view—almost exactly opposite of the 83-percent-favorable, 15-percent-unfavorable opinion of those who identify as Democrats.

So what about the independents? Among indies, 55 percent had a favorable view to just 40 percent unfavorable, and those who felt intensely were pretty evenly matched—28 percent of independents had a very favorable opinion and 27 percent had a very unfavorable view.

The Kaiser poll then looked at 311 voters who lived in one of 13 states that as of Feb. 8 had a gubernatorial or senatorial race rated by The Cook Political Report as a “Toss Up,” or in one of 21 congressional districts that were rated then as a Toss Up. In those battleground states or districts, 48 percent had a favorable view of Obamacare and 48 percent had an unfavorable opinion, with slightly more holding a very unfavorable view (33 percent) than a very favorable opinion (29 percent). Not surprisingly, the Kaiser poll found that issues involving changes to the Medicaid program, like lifetime-benefit limits and work requirements, also created huge party differences.

In short, where you stand on the ACA depends on where you sit. Democrats really like it, Republicans really don’t, and independents—who once didn’t like it much—now support it more than oppose. The numbers are a reminder, to both the single-payer crowd on the Left and the repeal-ACA and restrict-Medicaid advocates on the Right, that there is more to the electorate than just the base.

This story was originally published on nationaljournal.com on March 5, 2018