The impending passage of their tax reform bill marks a significant legislative achievement for Republicans and will give their candidates something to trumpet in next year's midterm elections. But Democrats are sensing an opportunity to run on it as well.

Seizing on key provisions that would disproportionally benefit wealthy Americans like President Trump, and variety of polls showing the public significantly opposed to the measure, Democrats see a potent economic issue for the 2018 campaigns.

Additionally, their path to the House majority runs through swing GOP districts in New Jersey, New York and California, states that are expected to be adversely affected by the legislation. When the House passed the penultimate version of the bill Tuesday -- a final, tweaked iteration is expected to be voted on Wednesday morning -- a dozen Republicans from those three states joined all lawmakers from the minority party in opposing it. And the fact that no Democrat in either the House or the Senate crossed the aisle to support the overhaul also indicates how the party foresees the political climate next year.

The tax bill "gives Democrats something very real to run on," said Jon Vogel, a former executive director of the Democratic Congressional Campaign Committee. "It was always hard to run against the Ryan budget because it was never real to voters. Now that this tax plan is becoming law, Republicans are going to wear this around their necks. ... It allows us to talk about a very real pocketbook issue for voters."

Democrats believe they have a menu of options to run with against Republicans next year, and GOP efforts to undermine the Affordable Care Act and the tax overhaul figure to be among the most attractive. The new tax legislation also repeals the mandate to buy health insurance, which opponents argue will drive up the cost of coverage as some policy holders decide to leave the marketplace.

While Republicans count the mandate repeal and the first major tax overhaul in three decades as significant accomplishments for their party and the Trump administration, Democrats see them as voter mobilization tools. And they don’t anticipate the public's approval rating of Trump or the tax bill to improve significantly between now and Election Day. Indeed, some see the two as linked and self-reinforcing.

"The unifying factor is opposition to Donald Trump, and this serves to elevate the threat," Vogel says.

Polls have shown a decline in approval for the tax legislation over the past several weeks. A new NBC News/Wall Street Journal survey released Tuesday found 41 percent think it is a bad idea, up from 35 percent in October. Support remained virtually unchanged at 24 percent. The survey also found that 63 percent say the plan was designed mostly to benefit corporations and the wealthy, while 22 percent say it was designed to help all Americans equally.

A CNN poll released ahead of the vote found similar scores. Opposition to the bill grew to 55 percent, up from 45 percent last month. The survey also found that 64 percent of independents and 95 percent of Democrats saw the bill as benefiting the wealthy. Meanwhile, 60 percent saw it as a benefit to the middle class.

Republicans argue that public opinion will improve once Americans start to see changes in their take-home pay and additional dollars in their wallets. "The results are going to make this popular," House Speaker Paul Ryan told reporters. And the GOP believes Democrats will be in a jam.

"Next year, when paycheck withholdings change and people start to feel the effects, I dare Nancy Pelosi and Democrats to run on protecting the old tax code and raising taxes on the middle class," said National Republican Congressional Committee spokesman Matt Gorman. "Good luck."

The partisan measure has drawn parallels to the Democrats' passage of the Affordable Care Act and the political repercussions it had for the party in the 2010 midterms. Back then, Democrats argued that public perception of bill would improve with the passage of time and the implementation of the law. But Republicans won 63 House seats that year and control of the chamber. Even Democrats who did not vote for the health care overhaul lost their seats, as they were tainted by the national party. Then-Speaker Nancy Pelosi was unpopular, and Republicans successfully used her as a boogeyman.

Still, Republican strategists are reluctant to draw too sharp a line between now and then. Guy Harrison, who was executive director of the NRCC during the 2010 cycle, said it's Democrats — particularly senators up for re-election in red states -- who are taking a risk by not supporting the legislation. "This group of senators are in a suicide pact," Harrison said. "Between reducing regulations and the tax cut agenda, Republicans have an ability to talk about increasing economic growth and getting jobs back and revitalizing America. They have an agenda to run on."

One silver lining for the GOP in the NBC/WSJ survey was that Americans say Trump's approach has made the economy better rather than worse, by a margin of 40 percent to 21 percent. Yet the same survey found that more voters viewed Democrats as better on the economy and taxes than Republicans, by 35 percent to 30 percent. And Democrats have noted that even positive perceptions about the economy have not translated into approval for Trump.

In addition to that dynamic, Democrats see the low approval of GOP leaders as working in their favor. Polling by the House Majority PAC, a group backing Democratic candidates, found Ryan's job approval at just 26 percent. Democrats argue that this number, in addition to Trump's low approval rating, will have an impact on how the tax bill is received in targeted GOP districts. The group's polling finds that in California's 25th District, which Hillary Clinton carried by seven percentage points, just 23 percent of respondents support Ryan. And in Virginia's 10th District, which Clinton carried by 10 points, only 20 percent approve of Ryan.

"The idea he's a credible salesman on this effort, or that Trump can push a message, is ridiculous because nobody believes what they are saying," said Charlie Kelly, executive director of House Majority PAC. "If I'm a factory worker in Cedar Rapids, I'm asking, 'What's the deal? Why are Ryan and Trump so focused on helping the ultra-rich?'"

Still, Democrats face a gamble of their own on the tax issue. A year is a long time in politics. And if politicians have learned anything from past debates over taxes, health care and entitlements, it is that it’s always politically difficult to take something away from individuals or groups.