Tennessee Rep. Marsha Blackburn launched a bid for the U.S. Senate Thursday by channeling Donald Trump: She touted her tendency to be "politically incorrect" and urged fellow Republican lawmakers to shape up.

The conservative eight-term congresswoman is considered a front-runner in next year's primary to replace Sen. Bob Corker. The Senate Foreign Relations chairman’s decision last week to retire jolted the GOP ahead of what is expected to be a challenging year for incumbents. Blackburn's entrance came just hours after Gov. Bill Haslam said, to the chagrin of many national Republicans, he would not throw his hat into the ring.

“Too many Senate Republicans act like Democrats or worse -- and that’s what we have to change,” she says in a three-minute announcement video. “I will fight every single day to make our Republican majority act like one.”

The Volunteer State lawmaker is aiming to tap into frustration among the party’s base regarding incumbents they perceive to be ineffective and standing in the way of the president's agenda. In her announcement, Blackburn underscored this sentiment, calling the Senate "totally dysfunctional," expressing support for Trump's immigration ban and pledging to "fight with him every step of the way to build that [border] wall." She also made reference to the controversy surrounding protests by NFL players. "Yes, I stand when I hear ‘The Star-Spangled Banner,’" said Blackburn, who introduced a resolution in Congress last week on national anthem etiquette.

This rhetoric stands somewhat in contrast to that of the senator she hopes to replace. Corker supported Trump's candidacy and was considered for Cabinet-level positions after his election. But over the past few months, he has emerged as a tough critic of the president. Just this week, for example, Corker suggested that the administration stands on the brink of mayhem.

"I think Secretary Tillerson, Secretary Mattis and Chief of Staff Kelly are those people that help separate our country from chaos," he told reporters on Wednesday after the secretary of state held a press conference to refute reports that he was contemplating resigning and had called the president a "moron."

Corker first turned heads in August, condemning Trump's response to the violence in Charlottesville, Va. The president, he said at the time, "has not yet been able to demonstrate the stability nor some of the competence that he needs to demonstrate in order to be successful."

Trump responded through Twitter, alluding to Corker's re-election in 2018: "Tennessee not happy!" he wrote. Corker, a former businessman, narrowly won his first race for the Senate in 2006, but was re-elected easily in 2012, winning 64 percent of the vote. But as he contemplated a third term, Republican rivals had thought about challenging him.

Conservative activist Andy Ogles has already launched a campaign. And others toyed with running, including state Sen. Mark Green, who withdrew as Trump’s appointee to be Army secretary after controversial comments he’d made surfaced, and Joe Carr, who unsuccessfully challenged Sen. Lamar Alexander in 2014. After Blackburn's announcement, Green announced a bid for her House seat, and the conservative group Club for Growth quickly endorsed him. Former Rep. Stephen Fincher is also thinking about a bid.

Though Haslam would have been considered a top contender had he decided to enter the race, he would have faced headwinds in an anti-establishment environment. Groups such as Club for Growth were already gunning for him. "Haslam decided not to run for the same reasons Sen. Corker is retiring — they know they would lose if they tried and can’t compete with true conservatives," argued Andy Roth, vice president of the club's PAC.

"Like a lot of other places, there's a dissatisfaction with elected leadership generally," said Tom Ingram, a state Republican strategist and former chief of staff to Lamar Alexander. "That's something incumbents need to take very seriously -- whether they're in the House or Senate or wherever. They're going to have to show performance."

Haslam's bowing out signals what could be a difficult environment ahead, especially after incumbent Sen. Luther Strange's defeat in Alabama last week. The Tennessee governor, who withdrew support for Trump's candidacy last year, said he preferred to finish his final term without the distraction of an additional campaign. But he also admitted, "I don't feel the same call to run for the Senate at this point."

With Haslam out of the race, Blackburn has the potential to consolidate broader support. Outside groups are assessing the race, but find her record and rhetoric attractive. "We're very, very interested in this race," Roth told RCP. Voters "don't like politicians who feed the swamp, and I think if there is a clear contrast in this race, it will be on that." Roth and others have also highlighted Blackburn's work at a state senator, when she fought her own party's governor on instituting an income tax.

Eric Beach of the pro-Trump Great America Alliance, which supported the victorious Roy Moore in Alabama, said Blackburn aligns with core issues on the president’s agenda. As the group mulls whether and how to get involved in the race, Beach noted that candidates like Blackburn could boost turnout. "There is an intensity to this Trump coalition the political establishment doesn't understand," he said.

Blackburn was a top supporter of Trump's candidacy, appeared as a surrogate during the campaign, and had a prime-time speaking slot at the national convention. The congresswoman continued her support of Trump after many of her colleagues abandoned him in the wake of the “Access Hollywood” recording. But she has also been critical at times. After Trump made disparaging remarks about a female MSNBC host, Blackburn issued a statement on Facebook. "This week’s inappropriate and pointless tweets from the President are a stark example of just what has gone wrong in our political discourse today," she wrote.

Trump won Tennessee with 60 percent of the vote. Blackburn ran ahead of him in her district, which covers the western part of the state, garnering 72 percent. And while she has been a member of Congress since 2002, she has built a profile in Congress outside of the so-called establishment.

Blackburn is also a frequent guest on the Sunday shows and cable news programs, and has appeared at various high-profile conservative gatherings, fueling speculation about her ambitions beyond the House.

“I’m a hard-core, card-carrying Tennessee conservative. I’m politically incorrect and proud of it,” Blackburn says in her announcement video. “I know the left calls me a wing-nut, or a knuckle-dragging conservative. And you know what? I say that’s all right, bring it on."