Amy McGrath, a retired Marine fighter pilot whose unsuccessful 2018 House campaign attracted national attention, will challenge Senate Majority Leader Mitch McConnell for his Kentucky Senate seat, she announced Tuesday.

The highly anticipated announcement keys up what is likely to be one of the most closely watched and well-funded matchups of the 2020 congressional campaign cycle, although even Democratic supporters have acknowledged that McGrath faces long odds to unseat one of the most powerful members of the GOP.

In a video announcing her campaign released early Tuesday, McGrath portrays McConnell as at the root of rancor and dysfunction in Washington.

“Everything that’s wrong in Washington had to start someplace. How did it come to this?” McGrath says in a video announcing her campaign. “Well it started with this man, who was elected a lifetime ago, and who has bit by bit, year by year, turned Washington in something we all despise. Where dysfunction and chaos are political weapons. Where budgets and health care and the Supreme Court are held hostage. A place where ideals go to die.”

I’m running to replace Mitch McConnell in the U.S. Senate. Everything that’s wrong with Washington had to start somewhere—it started with him. With your help, we can defeat Mitch and defend democracy. Join us: https://t.co/c4b0WAp4ji pic.twitter.com/DNLjFkHGua

— Amy McGrath (@AmyMcGrathKY) July 9, 2019

McGrath is the first Democrat to launch a serious challenge to McConnell so far. Talk show host Matt Jones and Kentucky Statehouse Minority Leader Rocky Adkins have also expressed interest in running.

Speculation about McGrath’s plans has been building for months. The Democratic Senatorial Campaign Committee has actively recruited her. And several outside groups have been working to oppose McConnell or entice McGrath to run, including Ditch Mitch, a political action committee dedicated to unseating McConnell, as well as the liberal political action committees VoteVets and End Citizens United.

Those groups hope to capitalize on what they perceive as signs of weakness for McConnell, who has consistently ranked among the least popular Senators in opinion polls of Kentucky voters — even after he notched some of his biggest victories as the majority leader, such as shepherding the passage of the GOP tax overhaul in 2017.

Democrats, still sore that McConnell blocked a Senate hearing for President Obama’s 2016 Supreme Court nominee, Merrick Garland, see the seat as a top target in 2020.

But some have also questioned whether McGrath can win a statewide race in Kentucky. Though her campaign videos went viral and helped her ultimately raised $3.3 million more than the incumbent, McGrath lost her 2018 challenge to Rep. Andy Barr by about 3 percentage points as she struggled to counter being depicted as “too liberal” for the district.

McConnell’s campaign wasted no time picking up on that theme, unveiling a website called wrongpathmcgrath.com with a video features McGrath quotes about abortion and health insurance and composite images showing McGrath alongside such liberal leaders such as Sen. Elizabeth Warren, D-Mass., and Rep. Alexandria Ocasio-Cortez, D-N.Y.

Welcome to the race, Amy. #KYSen pic.twitter.com/VdmKfFvTpI

— Team Mitch (@Team_Mitch) July 9, 2019

“Amy McGrath lost her only race in a Democratic wave election because she is an extreme liberal who is far out of touch with Kentuckians,” spokesman Kevin Golden said. 

McConnell, who is known as a relentless campaigner, plays up his relationship with President Donald Trump on his own website, and the two will be on the ballot together next year. The home page quotes Trump calling McConnell, “a true fighter for Kentucky,” and says that along with securing confirmation of conservative judges, the senator “delivered on President Trump’s promise to Make America Great Again.”

McConnell’s  website also indicates he would try to make one of McGrath’s potential strengths a liability. Of the $8.5 million McGrath raised last year, $5.3 million, or 76 percent, came from out of state, according to the Center for Responsive Politics. 

“Left-wing billionaires, progressive activists, and Hollywood liberals will fund our opponent,” McConnell’s website says. “They will raise millions to flood the airwaves with attack ads and baseless smears.”

McGrath and her supporters shrugged off such critiques.

“She has demonstrated everything it will take to win,” said Ryan Aquilina, executive director of the Ditch Mitch Fund. “She has a strong background, a really compelling personal narrative, and she can raise the money that it will take to win.”

Kentucky Democratic Rep. John Yarmuth told C-SPAN Newsmakers in June that if McGrath entered the race, it would attract the same level of national attention as the $124 million battle in 2018 between Democrat Beto O’Rourke and Republican Sen. Ted Cruz in Texas.

But McGrath’s chances will be complicated by Trump’s popularity in the state, Yarmuth said. In 2016, Trump got 62.5 percent of the vote, his fifth-highest percentage nationwide.

“The way I look at it, there will be no presidential campaign in Kentucky next year,” he said. “There hasn’t been in years, and I don’t anticipate there will be next year. But there will be $50, $60, $70 million spent on the Senate race, so I would think that most Kentuckians will be focused more on the Senate race than the presidential and that would give Amy a chance.”

As for potential primary challenges, Jones, who owns Kentucky Sports Radio in Lexington, said last month that national Democrats were solidly behind McGrath.

Adkins, who is more conservative than McGrath, told the Lexington Herald Leader that he had been “approached” about a run. He demonstrated in a failed gubernatorial bid that he could appeal to rural voters — a constituency where McGrath struggled in 2018 — but those attributes could hamper his ability to raise money outside the state, the newspaper reported.

From the Archives: We Reviewed Andy Barr, Amy McGrath and Beto O’Rourke’s Campaign Ads