Blackburn in. Bredesen in Too? The Senate Scramble Begins.

Here’s the truth: No one actually thought U.S. Sen. Bob Corker was going to leave office. At least, not willingly.

I didn’t think it. No one else I talked to thought it. Someone who planned to work on his re-election campaign told me Corker was definitely running. Corker even had a fundraiser the night before he announced he wouldn’t run in 2018.

Pretty much everyone in this state who could see him- or herself as a senator was focusing on 2020, in the hopes that Sen. Lamar Alexander, who’ll be 80 then, would decide to retire. (And if he didn’t, then the interest and turnout during a presidential election year would make up the difference.) Now everything is up in the air.

U.S Rep. Marsha Blackburn is the easy favorite to replace Corker. She’s got the money ($3.2 million on hand as of Sept. 30), she’s got the name recognition from almost 20 years in office, and she’s got the face recognition from her nonstop cable news appearances. She’s from Middle Tennessee — which at least hypothetically makes it easier for her to connect with voters on either end of the state — and she was out in front of the pack in her support of then-candidate Donald Trump, even speaking onstage at the Republican National Convention shortly before he formally accepted the party’s nomination for president.

Trump is still popular in Tennessee, unlike in the majority of the country, but even here his net approval ratings have dropped 23 percent since he took office nine months ago, according to a recent poll by Morning Consult. And elements of his agenda that Blackburn supports, such as repealing the Affordable Care Act and eliminating DACA, are highly unpopular, even in deep-red Tennessee. If Trump’s approval ratings keep falling, and if Blackburn keeps running and tying herself to Trump — two big “ifs” indeed — she could be vulnerable to attack from Democrats or a more moderate Republican.

Blackburn is already under attack for her co-sponsorship of legislation ostensibly designed to help end the opioid epidemic that actually prevented the Drug Enforcement Agency from cracking down on opioid distributors. Although the bill passed the House unanimously and was signed into law by President Barack Obama, a Washington Post/60 Minutes joint investigation strongly implied that sponsor Rep. Tom Marino (R-Penn.) and Blackburn knew the true intent of the legislation and tried to hide it from other members of Congress.

On Monday, Blackburn issued a statement saying, “If there are any unintended consequences from this bipartisan legislation … they should be addressed immediately.” But it seems almost certain that attack ads will link the legislation to the hundreds of thousands of dollars donated to Blackburn by pharmaceutical companies — watching 60 Minutes, you could imagine the interviews from DEA whistleblower Joe Rannazzisi being excerpted out of context and running over ominous music in such ads.

The Tennessee Democratic Party jumped on the controversy early Monday.

“At the crucial time when she should have been protecting us, Rep. Blackburn championed a bill that imprisoned even more Tennesseans in a devastating cycle of drug dependence,” said TNDP chair Mary Mancini. “Families all over Tennessee have been crippled by this crisis.”

“That Congresswoman Blackburn would champion legislation like this while Tennesseans face an opioid epidemic is all one needs to know about her priorities,” Democratic candidate James Mackler told the Washington Post on Monday. On Tuesday Mackler called for Blackburn to end her Senate run.

Mackler is so far the only Democrat running for Senate — and he announced his candidacy in April, when he thought it’d be just him against Corker, before ousted White House staffer and Breitbart News head Steve Bannon threatened to primary Corker, before the open seat attracted a lot more potential candidates from both parties.

Mackler is a young Nashville attorney with a made-for-public-office backstory. He joined the Army after 9/11, serving as a Blackhawk helicopter pilot with the 101st Airborne Division and then as a lawyer in the JAG corps. His supporters think he can be the next Jason Kander, the Missouri Democrat who almost upset Sen. Roy Blunt last fall. (One of Kander’s campaign ads, in which he assembled an assault rifle blindfolded while talking about his support for gun control, went viral.)

What Mackler’s supporters don’t mention is that Kander was a known political quantity who had served in Missouri’s state House and was already the elected Secretary of State of Missouri when he ran for Senate. Mackler has no previous campaign experience, and even some Democrats who really, really like him are worried about his lack of polish. He looks great on paper, but so far that hasn’t translated into him being able to work a room — and when your campaign is going to be outgunned by Republican donors and dark-money independent expenditure groups like Citizens United and the Club for Growth (both of which have already endorsed Blackburn), charisma is the only thing the Democrats can run on.

That’s why Chattanooga Mayor Andy Berke and Nashville state Rep. John Ray Clemmons are still mulling runs (as of press time), and why former Gov. Phil Bredesen has now said he might run after all, even though two weeks ago, he wasn’t interested. (The intervening factor? Likely pressure from Bill Freeman and other prominent donors who think a big-name moderate might have a chance at an open seat.)

But the biggest difference between Bredesen and Mackler, Berke and Clemmons isn’t name recognition — it’s the 30-year age gap. Will the 73-year-old Bredesen bring voters to the polls in November 2018 the way a 40-something candidate representing the possible future of the TNDP might?

The youth vote isn’t as important for the Republican Party, because in Tennessee, Republicans don’t need to worry about getting out the vote at all. Whether Blackburn is the eventual nominee or not, any Republican will be the heavy favorite against any Democrat — Al Gore Jr. was the last one to win a Senate race, and that was in 1990.

But Blackburn, 65, is the same age as the retiring Corker, who’s been in the Senate 12 years. Her one announced challenger, Andy Ogles, is in his 40s. And her other very likely (as of press time) challenger, former U.S. Rep. Stephen Fincher, is 44. Could that make a difference with voters?

If Fincher runs, he’s starting off with $2.4 million on hand, left over from his campaign funds from his House run. A farmer from the unincorporated area of Frog Jump in far West Tennessee, Fincher declined to run for a fourth term in 2016, citing family issues. In a recent interview with the Associated Press, Fincher said he needed to run the family farm because his brother was ill, but now he’s in a position where he can again consider a run for office.

Despite his six years on the Hill, Fincher still faces a name-recognition problem. And although he was elected as a tea party candidate in the sweep of 2010, Fincher has taken a very moderate position on a number of issues — to the point that some groups backed by the Koch brothers have already vowed to go after him if he runs.

“There have been many quality candidates suggested that are considering running for Bob Corker’s seat,” James Davis, executive vice president of the Koch brothers’ umbrella group, Freedom Partners Chamber of Commerce, told the Washington Examiner earlier this month. “Stephen Fincher is not one of them. Should he try to return to Congress, we will make sure Tennesseans are fully aware of his record.”

Ogles, as the former head of the Tennessee chapter of Americans for Prosperity, could possibly be the recipient of some Koch money. Auto dealer and conservative mega-donor Lee Beaman also promised to raise $4 million for Ogles, but that was when Ogles was planning to challenge Corker. Since Corker’s announcement, Ogles has been mostly quiet (and not returning calls from members of the press). But on Monday he told conservative website The Tennessee Star that Corker should resign as chair of the Senate Foreign Relations Committee.

“[It] is clear that Corker has lost the capacity to put America’s interests ahead of his petulant tantrums,” Ogles said, echoing calls from others on the far right for Corker to resign entirely after the senator spoke frankly to The New York Times about Trump’s competence as president.

But don’t look for Corker to resign anything, his chairmanship or his seat, anytime soon. And the senator barely seems perturbed by the recent attacks on him — when this reporter randomly ran into him at a restaurant in Chattanooga over the weekend, he appeared to be in very fine spirits.