When President Donald Trump tapped Sen. Jeff Sessions to be his attorney general last year, the last thing on anyone’s mind was what would happen to the Alabama Senate seat that Sessions would leave behind. With a Republican governor in a reliably Republican state, the assumption was that the governor would appoint a safe placeholder for the seat, who would then easily get elected to finish out Sessions’ term in the next election.

But fast forward nine months, and the Alabama governor who appointed that placeholder has resigned in disgrace. The placeholder, Sen. “Big” Luther Strange, finished second in the GOP primary to former state Supreme Court Chief Justice Roy Moore, who has been removed from the bench twice.

Strange, who had been planning to run for Senate before he was appointed, is now carrying the baggage of how he became a senator into the Sept. 26 runoff. But the heavier lift for Strange may be fending off attacks over his support from Senate Majority Leader Mitch McConnell, who himself was born in Alabama but has suddenly become the Nancy Pelosi of the right — every conservative’s favorite punching bag.

Even though McConnell and President Donald Trump have both endorsed Strange, and Trump announced he’ll stump for Big Luther on Saturday, the stakes in this race are much higher for McConnell. It’s easy to see Trump spinning any Strange loss as no big deal to him with an “I like Roy Moore, too!”

But there is no spinning the fact that McConnell has gone all-in for Strange. The Senate Leadership Fund, a McConnell-aligned super PAC, has spent more than $7 million attacking Strange’s opponents, including Moore, as insufficiently conservative.

More importantly, the usually behind-the-scenes McConnell has suddenly become an animating issue himself in the runoff. Moore has gone out of his way to say that he would not vote for McConnell for majority leader and has called the PAC spending from the Senate Leadership Fund “Mitch McConnell’s DC slime machine is spending MILLIONS to bear false witness.”

Dangerous currents

A Moore victory in the runoff could open the floodgates on conservative challengers lashing out at McConnell as a campaign tactic the way House GOP challengers ran against Speaker John Boehner in 2010 (and we all know how that ended).

It’s already happening in Arizona, where Sen. Jeff Flake’s primary opponent, Kelli Ward, has said the American people “are continually disappointed with the lack of results from career insiders like Mitch McConnell, Jeff Flake, and John McCain.”

In Nevada, Danny Tarkanian has blamed Senate leaders, including McConnell, for not getting Trump’s agenda passed.

“We are not getting it passed because we have senators that are already in office that have never supported the president and don’t support his America First agenda,” Tarkanian told Fox Business last month. 

The attacks on McConnell, from the president himself and from conservatives within the party’s ranks, are taking a toll on the Kentucky Republican in his national approval rating — a metric that McConnell most certainly doesn’t care about, but is relevant anyway. A PPP poll last month found McConnell now has a 9 percent approval rating in the country, including just a 15 percent approval among Trump supporters. 

That makes no difference in Kentucky, where McConnell remains popular, nor in the Senate, where McConnell’s real base of GOP senators still supports him strongly. But a man with a 9 percent approval rating is a no-lose proposition as a target for a conservative challenger looking to make a splash in a GOP primary, whether it’s in Alabama or Pennsylvania or Arizona.

With just 52 GOP seats in the Senate, the result of the Alabama runoff is crucial to the GOP majority McConnell has built. That’s because even if Moore were to defeat Strange, his path to the Senate over Democrat Doug Jones isn’t a sure thing.

Although he won statewide in 2012, Moore finished with 52 percent of the vote against the Democrat in the race, a victory, but not even close to Mitt Romney’s 60 percent result that same year. Moore has also been removed from the bench since then, after his order to state probate judges to refuse to implement the U.S. Supreme Court’s decision on gay marriage. Winning a Senate seat under those circumstances would be unprecedented, to say the least.

A broader worry within the Republican caucus is the effect that a potential Moore upset could have on other races across the country, signaling to other potential conservative challengers that this is the year to target incumbent Republicans, with Trump in the White House, but his agenda in need of reinforcements.

In a year that was otherwise shaping up to be a good one for sitting Republican senators in red states, the idea of a challenge from the right is the last thing any of them wants to contemplate.

A new target

Exactly why McConnell has become the go-to target for conservatives, and even for Trump, is not entirely clear.

McConnell himself has never been accused of being a moderate and the only real accomplishment that Trump can claim so far, the appointment of Neil Gorsuch to the Supreme Court, is due entirely to McConnell’s refusal to give Democrats a vote on Merrick Garland last year, as well as his decision to change the Senate rules to vote on Gorsuch this year.

McConnell could not deliver the Obamacare repeal-and-replace bill that he and every other Republican had been promising for the last seven years, but in McConnell’s defense, the legislation in front of the Senate was so deeply flawed that had it passed, it might have cost Republicans more seats in the midterms than passing nothing at all.

With all of that said, the job of a majority leader is not just to deliver an agenda his caucus can run on. McConnell has also taken it upon himself to protect his members (and therefore his majority) from primary opponents when they’re targeted at home. So far, the McConnell agenda hasn’t come through, but we’re nine months into this Congress, so it’s too early to give a grade on that one.

But we’ll find out next week how well McConnell can deliver when it comes to protecting his members in a primary. The results will have major implications, not just for Big Luther Strange, but for the entire GOP caucus in the Senate.  

Roll Call columnist Patricia Murphy covers national politics for The Daily Beast. Previously, she was the Capitol Hill bureau chief for Politics Daily and founder and editor of Citizen Jane Politics. Follow her on Twitter @1PatriciaMurphy.