The $1.5 trillion tax bill, hailed with glee and relief by Republicans eager to appease donors and desperate for the year's first major legislative win, is the most unpopular major piece of legislation to pass in decades.

That may sound remarkable, but it's not the only case where public opinion – exhaustively collected, analyzed and reported by pollsters, interest groups and political parties – appears to have had little impact on a matter of public interest. President Barack Obama's Deferred Access for Childhood Arrivals program to allow certain young immigrants to stay in the country is also overwhelmingly approved of by the electorate. But Congress failed to codify that program as it prepared to wind up for the year. Background checks for gun buyers, too, enjoys widespread public approval, polls consistently show – but that idea, too, never manages to get enough votes for passage.

So what's the congressional calculation? Do they not trust the polls, or care what Americans think? Lawmakers do indeed care, pollsters and political analysts say. They just care more about what certain people think and want.

"If you polled big donors, you'd find overwhelming support for the tax bill," says Stan Collender, executive vice president at Qorvis MSLGROUP and a leading expert on the federal budget and taxes. The presumption – "and it's a little risky, is that money can overcome the anger of the individual voter," Collender adds. "To them, somehow, $1,000 is worth more than 1,000 votes."

Polls show that the tax bill, passed on party-line votes, gets abysmally low marks from the public, a majority of whom also believe the package was designed to help the rich at the expense of the middle class. An NBC-Wall Street Journal poll taken shortly before the votes showed just 24 percent of Americans thought it was a good idea. A Monmouth University poll found that half of Americans believe their taxes will actually go up under the package, which provides for a bigger standard deduction, but limits on such popular deductions such as state and local tax payments and mortgage interest.

A CNN poll showed 55 percent opposed (10 points higher than the previous month), with 37 percent thinking they will be worse off.

According to an analysis by George Washington University political science professor Chris Warshaw, that makes the tax bill the second-most hated piece of legislation in the past quarter century-plus, behind only Trumpcare – which didn't pass. Even the bank bailout of 2008 and the failed Clinton health care plan of 1993 were more popular with voters.

Republicans are already nervous about losing control of the House next year, spooked by off-year elections which had Democrats making inroads in the politically critical suburbs and flipping 33 state legislative seats (compared to just a single blue-to-red flip). But lawmakers are more worried about vocal interest groups and wealthy donors who can cripple their campaigns before they get the chance to make their pitches to voters, experts say.

"It has a lot to do with money," says Lee Miringoff, director of the nonpartisan Marist Institute for Public Opinion in Poughkeepsie, New York, pointing to the "Citizens United" Supreme Court case which allowed corporations and interest groups to spend massive amounts of money to influence elections.

"We see the tremendous impact of the lobby community in the tax bill. Lobbying interests were very much dominant in drafting and creating this approach." And that means public opinion, so painstakingly quantified by pollsters candidates themselves hire, is often disregarded.

Not all matters should be decided by public polls, political veterans say, noting that congressmen and senators were elected to exercise their informed judgment on issues and balance public needs. If a pollster asked Americans if they thought schools, infrastructure and other public operations should be top-notch, they'd likely say yes. But they also might want to pay lower taxes, making the first goal harder.

But on several major issues in the news, the views of the public at large appear to have no effect on Congress.

For example, Americans overwhelmingly agree that so-called "Dreamers" – young people whose parents brought them into the United States illegally, and who have known no other home than America – should be allowed a way to stay lawfully, either with a path to citizenship or some kind of legal status. A recent poll by the nonpartisan Marist Institute for Public Opinion shows that a combined 81 percent of Americans want this, compared to 15 percent who believe they should be deported. The stay-here-legally side includes 67 percent of Republicans.

The problem, says Frank Sharry, executive director of the pro-immigrant group America'a Voice, is that lawmakers are divided into three broad groups – the pro-immigrant side, the build-the-wall side, and a group in the middle trying to balance a desire to be compassionate to Dreamers with a wish to maintain border security. While the hardliners against legal status may be in the minority, they are also often the loudest and most likely to punish a candidate for defiance, experts say.

"The path of least resistance inevitably becomes more attractive for people in the middle," Sharry laments.

Special interest groups across the board have outsized influence because of their financial resources to influence campaigns as well as their ability to rile up their rank-and-file members, analysts say. That explains, they say, how the National Rifle Association has been able to quash any effort to tighten up background checks for gun buyers, despite consistent evidence that the public wants it. A Quinnipiac University poll last summer, for example, showed that 94 percent of Americans endorse background checks for all gun buyers.

The current political environment, too, is to blame, says Tim Malloy of the Quinnipiac poll. "We are so polarized and people are so entrenched – either pro-Trump or anti-Trump. I think it's grown out of anger. It's an angry disillusioned country right now," Malloy says. "People at this point are almost impervious to the issues" themselves.

The public can fight back, and has: in 1988, Congress passed a law to provide catastrophic health coverage to seniors. The cost was shifted to the older Americans, who revolted (including by chasing the car of the then-Ways and Means Committee chairman, Rep. Dan Rostenkowski, D-Ill.). Congress repealed the law the following year.