President Trump’s first year has been marked by an almost complete lack of major policy wins. But that could come to an end this week. Congress is on the verge of passing a massive tax bill into law. It would be the first major legislative victory for Trump and the Republicans. And it would accomplish a long-held GOP goal: cutting the corporate tax rate.

But policy wins and political wins don’t always go hand in hand. Republicans who believe that failing to pass this tax bill will be a disaster for them in the 2018 midterm elections, like Trump and Sen. Lindsey Graham, are likely to be disappointed.

This tax bill remains historically unpopular. According to an average of nine surveys taken this month, 33 percent of Americans are in favor of it, and 52 percent are opposed. That -19 percentage point split between support and opposition makes it the least popular major tax bill since at least the Ronald Reagan tax cuts in 1981.

The GOP’s tax bill is still historically unpopular APPROVE YEAR POLLSTER TAX BILL YES NO DIFF. 1981 Gallup Reagan tax cut I 51% 26% +25 2001 Harris W. Bush tax cut I 49 37 +12 2010 ABC/WaPo Extending Bush tax cut I 54 42 +12 2013 ABC/WaPo Extending Bush tax cut II 45 38 +7 2003 Harris W. Bush tax cut II 45 39 +6 1986 CBS/NYT Reagan tax cut II 38 34 +4 1993 Gallup Clinton tax hike 34 44 -10 1990 Voter News Service H.W. Bush tax hike 41 52 -11 2017 December average* Trump tax cut 33 52 -19 *Average of surveys by CBS News, Gallup, Harris Interactive, Ipsos, Morning Consult, Public Policy Polling, Quinnipiac University, SurveyMonkey and YouGov.

Note: The polls included in this table used different question wording, including variations on “support,” “approve” and “favor,” as well as “oppose” “disapprove” and “vote down.”

So, all else being equal, we’d assume that passing an unpopular tax bill wouldn’t help a party’s chances heading into an election. Congressional Republicans seem to disagree — arguing 1) that the party will be rewarded for passing something even if it’s unpopular, 2) that voters will like the bill more once they understand its benefits and 3) that the bill will rally the base. I’m skeptical of each of those points — passing tax reform may not hurt Republicans, but it’s difficult to see it helping — and here’s why:

1. Republicans will be rewarded for passing something even if it’s unpopular

This argument, as made by Graham, is that Republicans want to pass something — anything — after failing to deliver on health care reform. A party that can’t do anything, this line of thinking contends, is worse than a party that passes unpopular bills.

But so far, there is little evidence that the general electorate is warming to the bill or Republicans as passage has gotten closer. Opposition has risen by 6 percentage points, from 46 percent last month to 52 percent this month. Trump’s approval rating has fallen from 38 percent when the House passed tax reform on Nov. 16 to 37 percent as of Sunday evening. Republicans continue to face a double-digit deficit on the generic congressional ballot. And by a 25-point margin, voters say they are less likely to vote for their member of Congress if he or she votes for the tax bill (43 percent, compared with 18 percent who said they’re more likely to vote for re-election).

So, there’s nothing in the polling to suggest that voters want the GOP to simply “pass something.” There’s also nothing in recent history that supports that line of thinking.

Indeed, for a while at least, Congress wasn’t in the habit of passing clearly unpopular bills. The closest analog, however, might be the passage of the Affordable Care Act in 2010. That bill was unpopular with the American public (though, not as unpopular as the GOP’s tax plan). Nevertheless, then-President Obama argued that his party needed to pass the health care bill to save Democrats’ fate in the midterm elections that year. Obama signed the ACA, and in the following midterms, Democrats lost their House majority. At least one study shows that Obamacare may have been the cause.

It is true that voters don’t like when nothing gets done in Washington. Political scientist Sarah Binder’s 2003 book “Stalemate” looked at how legislative gridlock in Congress affected the president’s approval rating, which is linked to his party’s fate in midterm elections. She found that when Congress and the presidency are controlled by the same party, the president’s approval rating does seem to drop when policy initiatives fail to advance. The effect, however, was relatively small. And as I’ve said, the alternative to getting nothing passed has typically been getting something at least mildly popular passed. As Binder was quick to point out to me over email: “Presidents are held accountable for their party’s overall record when they also control Congress — so it’s hard to escape accountability for an unpopular bill.”

2. Voters will like the bill more once they see the benefits

Perhaps the biggest public-opinion problem with the GOP bill is that voters believe it will mostly benefit the rich. Most Americans don’t think they will get a tax cut. But, as Ben Casselman and Jim Tankersley of The New York Times wrote, most Americans will get a tax cut under the bill (at least in the short term). As House Majority Whip Steve Scalise said, “Whatever the polling data is that’s out there today doesn’t recognize just how powerful this bill is going to be to put more money in the pockets of hard-working families.”

But we’ve heard Scalise’s argument before, and it hasn’t panned out. Before the Reagan tax cuts of the 1980s and the Bush tax cuts of the 2000s, Republicans argued that the middle class would benefit. Yet the percentage of Americans who thought those policies helped the richest Americans the most actually rose over time. With regard to the 1981 Reagan tax cuts, that number went from 59 percent in April 1981 to 69 percent in July 1984. And with regard to the 1986 Reagan tax cuts, it climbed from 48 percent in October 1986 to 65 percent in April 1988. For the Bush tax cuts, the percentage of Americans who thought the rich benefited the most went from 55 percent in April 2001 to 60 percent in October 2004.

3. This bill will help rally the base

Turnout is always lower in midterm election years than in years when a presidential race is on the ballot. And this drop in turnout tends to disproportionately hurt the party that controls the presidency. In other words, Republicans really need their base voters to turn out in 2018. Republican U.S. Rep. Chris Collins of New York said this about the tax bill: “We’ve got to deliver this to keep our base enthused to turn out in the midterms.”

I get where Collins is coming from, but the polling just doesn’t support his view.

For one, if Republicans want to goose turnout, taxes aren’t the issue to use. In the latest YouGov poll, only 8 percent of self-identified Republicans said taxes were the most important issue to them — behind the economy, terrorism, Social Security, health care and immigration. According to Gallup, just 2 percent of all Americans say taxes are one of the most important problems facing the country. If anything, the polling indicates that Democratic opposition to the tax bill is more deeply felt than Republican affection for it. That is, passing this bill might end up firing up Democrats to vote more than Republicans.

To understand how lackluster these numbers are for the Republican base, consider health care polling from earlier this year. In a May Gallup poll, health care was tied for the most important problem among all Americans. Democrats, to this day, say health care is the most important issue to them. The 24 percent of Democrats who list health care as No. 1 is three times the share of Republicans who put taxes on top.

Perhaps the most convincing argument for Republicans to pass their tax reform legislation, from an electoral standpoint, is one that polling can’t shed light on. Some Republican lawmakers believe that if they don’t pass the bill, donors will be less likely to give them money.

They may be right. (However, the GOP tax plan could hurt many wealthy donors in key fundraising areas like New York and California, and some of those people are threatening not to donate.) But the point of fundraising is to turn around and use donations to persuade and turn out voters. There isn’t much of a reason to think an unpopular tax bill will help Republicans do that.