Shortly before passing a far-reaching but unpopular bill on a party-line vote, the speaker of the House assured critics that people would like it once they felt its benefits.

That was 2010, and it didn’t work out for Nancy Pelosi, the Democrat in charge of the House at the time, or for the Obama healthcare bill. It remained unpopular, even after health coverage was extended to millions of people. Democrats lost the House that November and the Senate four years later.

Now, Pelosi and her party will try to turn the tables, targeting the GOP’s main achievement of 2017: tax legislation that, so far, rates poorly with the public. Republicans are pitching its middle-class benefits and potential economic growth to win over wary voters, but Democrats have united in labeling it a “tax scam” that benefits the wealthy and corporations.

“The American people will see through what this is, which is a scam,” said Rep. Ben Ray Luján, D-N.M., who chairs the House Democrats’ campaign arm. “This bill is terribly unpopular across America,” he said, adding that the party’s internal polling shows it to be unpopular “especially in swing states.”

House Speaker Paul Ryan, R-Wis., says he’s utterly untroubled by Democrats’ threats.

“No concerns, whatsoever,” Ryan said Tuesday during a news conference. He added: “Results are going to make this popular.”

Once American wage earners see their paychecks in February 2018 — after employers have adjusted withholding — they’ll start to appreciate what a boon they’ve received, he said. He and other GOP leaders also cite what they say will be a major boost to the economy, pushing annual growth to 3 percent.

Polls suggest Democrats are winning in the early rounds. Half the public thinks they’ll pay higher taxes under the Republican overhaul, according to a Monmouth University poll conducted from Dec. 10 to Dec. 12 that had similar findings to other studies. A NBC/Wall Street Journal poll released Sunday found that voters prefer Democrats over the GOP to run Congress by 50 percent to 39 percent, a margin that election analysts say could flip both chambers.

“People say the proof’s in the pudding. The proof’s in the paycheck,” GOP Sen. Rob Portman of Ohio said Tuesday during the debate that preceded the Senate vote on the tax bill.

Plenty of paychecks may not rise that much, based on an analysis this week. In 2018, the bill’s average tax cut for the bottom 80 percent of earners would be $675, according to an analysis by the Urban-Brookings Tax Policy Center. That’s about $13 a week.

It’s also smaller than a one-year, $800 tax cut for married couples in 95 percent of working households that was part of the 2009 economic-stimulus package. That earlier tax break bombed politically — just 12 percent believed they got a tax cut, a 2010 poll showed.

Higher earners will get a larger break next year, an average of $50,000 apiece for the top 1 percent and $190,000 for the top 0.1 percent, the policy center’s analysis found.

Regardless, if Republicans can persuade the public of their bill’s broad benefits, few voters will examine the fine print — and the legislation, which represents the party’s first major success this year, appears to have energized its leaders.