Trump won't get to hand-pick McConnell's successor — just look at what happened to Jim Jordan

• Mitch McConnell is stepping down, and Republican senators have months to decide who succeeds him.
• The end of his reign marks a shift in the GOP, but Trump won't get to fully decide the next leader.
• Trump forcefully backed Jim Jordan's House speaker bid in October. It crashed and burned anyway.

Senate Minority Leader Mitch McConnell's reign will end later this year, and there's already plenty of speculation about the role that former President Donald Trump will play in choosing the next Senate GOP leader.

It's very early in the race, and it's unclear how many contenders will emerge — the election won't happen until November.

Sen. John Cornyn of Texas — of the "three Johns" who have long been considered to be potential McConnell successors — announced his candidacy on Thursday morning, the first candidate to do so.

But one thing's for sure: Trump's not going to hand-pick the next Senate GOP leader.

That's not to say Trump's endorsement, or at least having a strong working relationship with him, will be worthless. In fact, it will be quite important, given that he is all but certain to be the party's presidential nominee, and the next president if he defeats Joe Biden in November.

And the departure of McConnell — who has essentially no relationship with Trump and has yet to endorse the former president — is certainly a sign of the decline of an older generation of conservativism within the GOP.

But there are several factors to consider when assessing the role that Trump will play in choosing McConnell's successor, many of which can be gleaned from the chaotic succession battle that House Republicans endured after the ousting of former Speaker Kevin McCarthy in October.

GOP senators will almost certainly elect their leader through a secret ballot

That's how it's typically been done — behind closed doors and out of the public eye.

It's how they dealt with the first-ever challenge to McConnell's leadership bid last November, when the Kentucky Republican handily defeated Sen. Rick Scott of Florida by a 37-10 margin.

While plenty of senators have publicly stated how they voted, we still to this day do not have a complete account of who voted for Scott.

Trump's power comes from his sway over GOP base voters, not so much his relationships on Capitol Hill.

There are plenty of GOP senators who have likely endorsed Trump not because they personally feel that he is the best man for the job, but because they're not interested in crossing their voters.

When voters don't have to know how you voted, that pressure is significantly diminished.

Trump couldn't seal the deal for Jim Jordan, even when the vote was public

It may feel like ancient history by now, but House Republicans struggled for three weeks in August to choose a speaker.

One of those candidates was Rep. Jim Jordan of Ohio, a staunch Trump ally who won the former president's backing early on.

But it wasn't enough. House Republicans first chose House Majority Leader Steve Scalise to be their candidate, only handing the nomination to Jordan after Scalise dropped out.

And when Jordan took the vote to the House floor, he lost — publicly — over the course of three successive votes as he faced a revolt from Republicans who were opposed to his bare-knuckle brand of politics.

It's all the more striking when you consider that the House is generally more prone to Trump's influence than the Senate, largely owing to the fact that House members face voters every 2 years.

The Ohio Republican later dropped out after putting up the worst showing for a speaker candidate since the Civil War.

So how much does Trump matter really?

It will depend on what happens in the presidential election, which will almost certainly take place before GOP senators vote on their next leader.

If he wins, Trump has something akin to a veto — if he really, really doesn't want a particular candidate to become the next Senate GOP leader, it's going to be a problem for that person.

That's the lesson one might draw from House Majority Whip Tom Emmer, who ended his own speakership bid just four hours after winning the nomination after being called a "RINO" by Trump.

It will be important for the eventual GOP leader to demonstrate that he or she could work with Trump if he's elected, but it won't be the only thing.

GOP senators will be looking for someone who ticks a variety of other boxes, including being a prodigious fundraiser, having a good sense of the internal politics of the conference, and potentially making changes to the way the party approaches politics.

For an early example of this, consider Cornyn's statement on entering the speaker's race.

While the Texas Republican briefly mentions helping Trump "advance his agenda" as the party's whip, most of his appeal deals with other topics, including his role in helping the party to gain Senate seats and his plans to reform the way the chamber operates.