House Democrats are hoping to use Sen. Mitch McConnell's "legislative graveyard" as a messaging tool to topple GOP candidates in 2020.

McConnell (R-Ky.), the Senate majority leader, is embracing his role as a roadblock to the Democrats' legislative agenda, casting himself as the "Grim Reaper" poised to kill the Democrats' top policy priorities. The barrier has frustrated Democrats as they fight to advance legislation they promised voters in 2018, but they also see it as a political gift heading into next year's elections.

Just this week, the House passed legislation granting legal protections to so-called Dreamers, immigrants brought to the country illegally as children. Democrats also hope to soon pass an increase to the minimum wage, and measures on climate change, health care and gun safety have already been approved.

Those proposals poll well nationally, and Democrats think voters - particularly those fed up with Washington gridlock - will take notice if McConnell simply ignores them, as he's vowing to do.

"He's an issue in this campaign," said Rep. Jim McGovern (D-Mass.), chairman of the powerful House Rules Committee. "I don't know what the hell he's for, I only know what he's against. ... Anything that helps working people, or helps those struggling to get into the middle class, he's against."

McGovern is hardly alone. Speaker Nancy Pelosi (D-Calif.) has made it routine to denounce McConnell's "Grim Reaper" promise as a barrier to any progress on Capitol Hill. This week, she marked the first 150 days of the Democrats' House majority by rattling off a slew of proposals already passed by the lower chamber that now sit idle in the Senate. The list includes voting rights protections, campaign finance reforms, pay equality for women, a net neutrality bill and protections for the LGBTQ community.

"We're very proud of the work that we have done to send over to the Senate, where Mitch McConnell has said he's the 'Grim Reaper' - it's a Senate graveyard," she told reporters in the Capitol. "We have news for him: It's alive and well in the public, and he will be hearing from the public, hopefully very soon."

McConnell and the Republicans are punching back, dismissing the Democrats' proposals as frivolous messaging bills designed to energize the Democrats' base but without a chance of becoming law. Aside from the partisan nature of most of those bills, the Republicans note, they also have little chance of winning President Trump's signature.

"This isn't a serious strategy to govern. They're passing bills saying that this is what they want, but they know that they're strictly basing their strategy on what polls well and not what can get into law," said a Senate GOP aide.

"They're doing everything for political reasons, and we're actually the adults in the room."

Not everything is partisan warfare on Capitol Hill. McConnell and the Democrats have come together on numerous occasions to enact must-pass legislation, like funding for the federal government. And Democrats feel they have an ally in the Senate majority leader as they negotiate a deal to raise spending caps later in the year.

"Three or four times before this we've had a deal on a replacement for the sequester," House Majority Leader Steny Hoyer (D-Md.) said this week. "Those deals dealt with two-year cycles, and I think that's what Sen. McConnell and I would both like to do again."

Through the lens of political messaging, however, Democrats see a useful foil in McConnell, who has spent much of the year focused on confirming conservative Trump appointees, including almost two dozen judges, in lieu of passing policy bills. By casting McConnell as the face of Washington gridlock, Democrats hope to portray the entire GOP as uninterested in governing - at the expense of the middle class.

Rep. Hakeem Jeffries (N.Y.), chairman of the House Democratic Caucus, blasted McConnell this week as the Senate's "Rip van Winkle," urging upper-chamber Republicans "to wake up from their legislative slumber and do their job." And the Democrats' campaign arm is vowing to make what they consider McConnell's stonewalling a national theme in their campaign messaging.

"While we're delivering for Americans, Mitch McConnell and the Republican held Senate brag about being a tool of Washington special interests," Rep. Cheri Bustos (D-Ill.), head of the Democratic Congressional Campaign Committee, said in an email. "It would be funny if it weren't so recklessly harmful for the folks we represent.

"The American people know who's working on their side and who's working against them," she continued, "and we'll make sure that message is reinforced when it's election season."

McConnell, for his part, has been characteristically defiant in the face of the attacks. In a Wednesday interview with Fox News Radio, the six-term Kentuckian noted that he'd dubbed himself "Darth Vader" during the campaign finance battles of years past. And he's relishing the thought of blocking Democratic proposals like "Medicare for All" and the Green New Deal - a role he sees as "the firewall against socialism."

"I've kind of enjoyed playing off of my enemies over the years, and in fact the 'Grim Reaper' title I gave myself," he told Fox. "Happy to embrace it."

Republican campaign operatives are also welcoming the Democrats' messaging campaign, saying it will only help GOP candidates at the polls next year.

"The socialist Democrats highlighting Leader McConnell's efforts to block their extreme socialist policies is an in-kind donation to Republicans across the country," Michael McAdams, spokesman for the National Republican Congressional Committee, said Thursday in an email.

McConnell is up for reelection in 2020, and Democrats are scrambling to field a prominent candidate to challenge him. Senate Minority Leader Charles Schumer (D-N.Y.) met earlier this year with Amy McGrath, a former Marine pilot, in hopes of recruiting her. McGrath lost a close race against Rep. Andy Barr (R-Ky.) in 2018, attracting national attention as one of the top Democratic fundraisers of the cycle, but she has so far declined to enter the Senate contest.

Matt Jones, a popular sports radio host, has also flirted with the idea of jumping into the race.

Kentucky is a Trump stronghold - the president won the state with 63 percent of the vote in 2016 - but polls show that McConnell's approval rating has been underwater this year.

Democrats hoping to use the majority leader as a national soundbite are also hoping Kentucky voters hear the message.

"As we approach the next election, he - along with Donald Trump - will be two major issues where people are going to have to decide whether they want to continue or not," McGovern said.

"If you want this country to run, you've got to get rid of the Grim Reaper."