U.S. Rep. Marsha Blackburn, R-Tenn., is entering the 2018 U.S. Senate race to replace retiring Sen. Bob Corker, ending a week's worth of speculation and immediately catapulting her to front-runner status as others consider launching their own bids.

More:Sen. Bob Corker will not seek re-election next year

In an online video released Thursday, Blackburn touted her conservative credentials while in Congress and the Tennessee legislature and her support for President Donald Trump and his policies.

Calling the U.S. Senate dysfunctional and "enough to drive you nuts," the Brentwood, Tenn. Republican says that ineffectiveness is why she's decided to enter the race.

"I know the left calls me a wingnut or a knuckle-dragging conservative. And you know what, I say that’s all right, bring it on," Blackburn says in the nearly three-minute video.

Her announcement came less than an hour after Gov. Bill Haslam, who was weighing a bid for the seat, said he will not launch a campaign.

More:Gov. Bill Haslam won't run for retiring U.S. Sen. Bob Corker's seat

Touching on the Senate's failure to repeal the Affordable Care Act, Blackburn says, "too many Senate Republicans act like Democrats or worse."

She touts her support for building a wall along the U.S.-Mexico border and her effort fighting against a GOP-led state income tax plan when she was in the legislature.

At one point in the video, Blackburn even quotes former President Andrew Jackson, a Tennessee Democrat, without naming him, saying, "One man with courage makes a majority."

"Courage comes in both genders and I'm running for the U.S. Senate because I'll fight every day to make our Republican majority act like one," she said.

The announcement from Blackburn, 65, comes after Corker said on Sept. 26 he would not seek a third term, sparking a frenzy of interest in the race among Tennessee politicians.

More:Sen. Bob Corker will not seek re-election next year

More:Gov. Bill Haslam says he's considering running for Bob Corker's U.S. Senate seat

Blackburn's candidacy affirms what many had expected since Corker's announcement.

Although conservative activist Andy Ogles is the only other Republican in the race so far, Haslam was encouraged by many, including U.S. Sen. Lamar Alexander, to consider running.

More:Marsha Blackburn, Diane Black still back Donald Trump

More:In wake of Trump's NFL comments, Marsha Blackburn files resolution on national anthem etiquette

In the lead up to launching her campaign, Blackburn commissioned internal polls which her campaign said indicated she would either defeat Haslam or be within the margin of error in a head-to-head match up if the election were held today. One internal poll noted while Haslam remains extremely popular in Tennessee, among those who consider themselves conservative Blackburn leads the way.

Although Blackburn did not say how much money would be needed for the campaign, her federal political action committee has $3.1 million available.

Blackburn has long been seen as a leading contender if a U.S. Senate seat were to open and her name has been on the rise in the national scene in recent years.

In 2015, she was encouraged to run for House speaker. She has spoken at the last three Republican National Conventions, including last year when she had a prime-time speaking slot.

If Blackburn were to win, she would become the first woman to represent Tennessee in the U.S. Senate.

Personal life and politics

Born in Mississippi, Blackburn has a bachelor's degree in Home Economics from Mississippi State University. She lives in Brentwood and is married with two children. She owns a promotion-event management company.

Blackburn's first foray into politics came in 1989 when she was named chair of the Williamson County Republican Party. In 1992, she unsuccessfully ran for Congress and served as a delegate to the Republican National Convention.

In 1995, then-Gov. Don Sundquist appointed her to serve as executive director of the Tennessee Film, Entertainment and Music Commission. Three years later she was elected to the state Senate.

Blackburn was elected to represent Tennessee's 7th U.S. Congressional District in 2002, when she got 40 percent of the vote in the Republican primary.

Since then, Blackburn has handily defeated all of her opponents. In five of her eight primary elections, including last year, Blackburn has faced no opponent. In all of her general elections, she received more than 66 percent of the vote.

Despite her longevity in Congress — Blackburn is the second-longest serving Republican member of the state's congressional delegation — she has managed to avoid the notion that she is entrenched in Washington, D.C.

Over the years, Blackburn has fought to lead the charge on music industry-related issues and rolling back net neutrality, the federal rules that govern internet providers.

She has also toed the party line, touting oft-espoused Republican positions on everything from immigration — she's sponsored bills to allow law enforcement to deport undocumented residents — to abortion and the Second Amendment.

Last year, she spearheaded the House Select Investigative Panel on Infant Lives, which formed in the wake of undercover videos surrounding Planned Parenthood.

Blackburn currently serves on the House Committee on Energy and Commerce and is chair of the Subcommittee on Communications and Technology.

Although its unclear whether the president, whose candidate lost in a recent Alabama Senate race, will make an endorsement in next year's election, Blackburn has largely embraced Trump. She served on his transition team and was believed to be under consideration for a Cabinet post and in recent months she has frequently appeared on national television defending Trump.

In the wake of Trump's criticism of NFL players who protest while kneeling during the national anthem, Blackburn introduced a resolution to remind Americans about proper etiquette.

Among the few times she criticized Trump came in June after his Twitter tirade against cable television hosts Joe Scarborough and Mika Brzezinski.

Support for Trump could play a role in next year's Aug. 2 primary election. Other Republicans mulling a run include former U.S. Rep. Stephen Fincher, Nashville surgeon Manny Sethi and Joe Carr, who ran and lost to U.S. Sen. Lamar Alexander in 2014 and U.S. Rep. Diane Black in 2016.

Carr confirmed Thursday he would not enter the race and vowed to support Blackburn.

Carr said he’s pledged that his political action committee, Stand Firm America, would be backing Blackburn as well. He said the PAC currently has $500,000 cash-on-hand.

Nashville attorney and Iraq War veteran James Mackler is the lone Democrat to launch a campaign so far although Chattanooga mayor Andy Berke and state Sen. Jeff Yarbro are weighing their options.

In her announcement, Blackburn did not say who has been hired to help run her Senate campaign.

Dave Boucher and Joey Garrison contributed to this report.

Reach Joel Ebert at jebert@tennessean.com or 615-772-1681 and on Twitter @joelebert29.