Democrats have unleashed a concerted, coordinated effort to undercut GOP candidates in competitive Senate and House races by charging them with blocking an extension of a payroll-tax cut — even though the Republican leadership has made it clear that it supports it.

For Democrats, the tax cut presents an ideal opportunity to meld President Obama’s “We can’t wait” message — which accuses Republicans of obstructing economic progress — with accusations of GOP hypocrisy for giving the green light to tax cuts for the wealthy while insisting middle-class tax relief pay for itself.

The conversation in Congress has moved from whether to support an extension of the tax cut to where to find the dollars to pay for it — Republicans object to Democratic plans to pay for it with a tax on millionaires — but no matter which way the debate goes, Democrats aren’t taking their foot off the gas in their attacks.

In at least four states — Ohio, Florida, Massachusetts and Indiana — the state Democratic Party is targeting incumbent Republican senators or leading candidates on an issue where it believes voters are clearly on its side. 

A Democratic operative in one of the states confirmed that the drive is being centrally coordinated, with research and policy stances being shared among the states. The Democratic Senatorial Campaign Committee (DSCC) declined to comment on any coordination efforts, focusing instead on what it deemed a divergence of priorities between the parties.

“Republican senators and candidates have shown that they’re willing to do anything to protect millionaires, even raise taxes on the middle class, and that will be a liability for them with voters next year,” DSCC spokesman Shripal Shah said.

The Democratic Congressional Campaign Committee (DCCC) is including the issue in a slew of robo-calls, Internet ads and live phone calls in the districts of 30 GOP House members. Republican Reps. Paul GosarPaul GosarHouse GOP not sold on Ryan’s tax reform plan Bipartisan push grows for new war authorization The Hill's Whip List: 19 GOP no votes on new ObamaCare replacement bill MORE (Ariz.), Dan Lungren (Calif.), Allen West (Fla.) and Sean DuffySean DuffyFlood insurance overhaul is progressing in House Puerto Rico statehood bid a total failure GOP rep dismisses Mueller probe: 'What the hell are we investigating?' MORE (Wis.) are among those targeted.

Democrats in Massachusetts hit GOP Sen. Scott Brown on Wednesday for protecting the rich while burdening the middle class, arguing that 3.4 million households in the state would be hit by a $1,000 tax increase if the extension doesn’t pass.

“Scott Brown is ready to raise taxes on middle-class families already struggling to get back on their feet in order to protect millionaires and billionaires, just like every other Washington politician who’s forgotten where they came from and who they represent,” Massachusetts Democratic Party Chairman John Walsh said Wednesday in a news release.

But the day before, Brown, who is facing a tough reelection fight in a Democrat-heavy state, said he was in favor of extending the tax cut. He even moved to the left of many Democrats on Tuesday by maintaining that the extension needed no offset elsewhere in the budget.

“It wasn’t paid for before, so why is it paid for now? Through economic activity, it will pay for itself,” Brown said.

The Massachusetts Republican Party criticized the Dem attack line.

“The Massachusetts political machine is so eager to misrepresent Sen. Brown’s record that they are attacking him for opposing a tax cut that he actually supports,” said Tim Buckley, a spokesman for the state GOP. “It just goes to show how out of touch they are on the important issues of the day.”

In Ohio, Democrats are faulting state Treasurer Josh Mandel, the front-runner in the GOP race to take on Sen. Sherrod BrownSherrod BrownMajor progressive group rolls out first incumbent House endorsement Dems push for more action on power grid cybersecurity Senate Banking panel huddles with regulators on bank relief MORE (D-Ohio), for not taking a position on the tax cuts, even as he travels to Washington for a pair of Wednesday fundraisers.

“I support reducing the tax burden on middle-class Americans by extending the payroll-tax cut,” Mandel told The Hill. “At the same time, Sherrod Brown needs to step up and cut excessive spending elsewhere in the federal budget to ensure that Social Security and Medicare are not negatively impacted.”

In Florida, Democrats touted a report released Wednesday by the Obama administration showing that 9.1 million middle-class residents in the state would benefit from the extension. And because Sen. Marco RubioMarco RubioSenators urge Trump to do right thing with arms sales to Taiwan Why liberals should support Trump — not Obama — on Cuba policy The Memo: Trump seeks to put his stamp on nation MORE (R-Fla.) is expected to support the extension as long as the millionaire’s tax falls by the wayside, Democrats called him out for favoring the interests of those who “fly in a corporate jet, represent a special interest or could offer the senator a sweetheart deal that benefits him” over the needs of the middle class.

Alexander Bolton contributed.