Sen. John Cornyn (R-Tex.) speaks on Capitol Hill. (Pablo Martinez Monsivais/Associated Press)

It’s hard to imagine describing Senate majority whip as a dead-end job. You’re the No. 2 member of Republican leadership, so important that you get a security detail, an office suite just off the Senate floor and invitations to top meetings at the White House.

Yet increasingly, that position has become the last stop on the leadership ladder because of a quirk in the internal rules of Senate Republicans. It’s a small but critical distinction now echoing through Washington as President Trump seeks a new director of the FBI who will oversee the counterintelligence investigation into Russian intervention in the 2016 presidential campaign.

Senate Majority Leader Mitch McConnell (R-Ky.) is the only person in GOP leadership not to face a limit on the number of terms he can serve in that top post. From the least powerful committee chairmen’s gavels to the highly influential majority whip post, Republicans otherwise impose on their leaders a limit of three two-year terms.

So now, faced with his own limit at the end of next year, Sen. John Cornyn (R-Tex.) is considering leaving behind his whip job to become director of the FBI, having interviewed with Attorney General Jeff Sessions over the weekend for the position.

The former Texas attorney general, a member of the Judiciary Committee since winning a Senate seat in 2002, is not merely looking for another top perch because he is effectively topped out in the Senate. Those who know him point to his close friendship with Sessions and a genuine wish to try to calm the ranks at the FBI following Trump’s firing last week of James B. Comey.

(Victoria Walker,Monica Akhtar/The Washington Post)

On Monday, Cornyn declined to comment on speculation, even as colleagues rushed to his side during a vote to chat him up about the prospect. “I’m not really talking about that today,” Cornyn told reporters.

But Cornyn’s long-term ambition is no secret: majority leader.

For more than a decade, Cornyn has taken the tough jobs that other senators don’t want, the sorts of tasks that earn credit with colleagues and help line up support for internal leadership races in the future. Cornyn served a stint atop the Ethics Committee, he served four years in the grueling job of campaign chairman, and, since January 2013, he has been Republican whip — a sometimes tedious job that requires plenty of time on the Senate floor, jousting with Democrats.

Less than two weeks ago, Cornyn acknowledged to Politico that succeeding McConnell was a longtime goal, calling it “something I would be interested in doing.”

But he also has no plans to challenge McConnell, who remains popular among Republicans. “He enjoys the broad support of our conference. And so I think a lot depends on what his decision is going to be,” Cornyn told Politico.

An additional factor is that a number of Republicans — including McConnell — have hinted that they would like to see someone else, perhaps someone out of politics, succeed Comey at the FBI. Whether that sentiment plays a role probably depends on how much Cornyn wants the job — and how much Trump wants him for it.

If Cornyn does leave the Senate, it should not come as much of a surprise.

Three of the past four Republican whips have surveyed the Senate scenery and decided to retire, heading for riches on K Street rather than returning to life among the rank and file. The most recent example was Jon Kyl (R-Ariz.), a popular policy wonk among conservatives who retired from the Senate at the end of 2012.

Kyl had two years left on his term as whip, but he decided to retire anyway. Serving the full time would have required running for another six-year term to represent Arizona, leaving him out of the leadership for the final four years. He instead joined Covington & Burling as a lobbyist.

Over the past 20 years, McConnell is the only Republican whip who has ascended to the top leadership post. That’s because he had the good fortune of taking that job when Bill Frist (R-Tenn.) became majority leader and announced he would serve only four years atop the GOP caucus, then retire at the end of 2006.

Now, after more than a decade as Republican leader, McConnell is sending signals that he will run for reelection in 2020, when he will turn 78. Next year, McConnell will become the longest-serving Republican leader; if Kentucky voters and his colleagues kept reelecting him, he would surpass Mike Mansfield (D-Mont.) in 2023 as the longest-serving leader of either party.

No one knows whether McConnell will willingly step aside at some point, allowing Cornyn and other junior Republicans to run for the position. McConnell’s autobiography, after all, is titled “The Long Game.”

That Cornyn faces a term limit, and McConnell does not, is almost an accident of history. Back in 1995, after winning the majority, a group of Young Turks challenged the seniority of the committee chairmen after one of them, moderate Republican Mark Hatfield (Ore.), bucked the party by voting against the constitutional amendment to require a balanced budget.

A task force, led by then-Sen. Connie Mack (R-Fla.), recommended imposing term limits of six years as committee chairman. The “old bulls” fought back and said that if they had to face a limit, then leadership posts should also. “This is jamming us into a pup tent,” Sen. John H. Chafee (R-R.I.), a leading moderate, told The Washington Post at the time.

Republicans later voted to impose limits on every post — except leader, given that their majority leader at that point, Robert J. Dole (R-Kan.), had already been running the caucus for almost 10 years.

On Bloomberg TV Tuesday morning, McConnell said that he has recommended Merrick Garland, the chief judge of the U.S. Court of Appeals for the District of Columbia Circuit, be the new FBI director. This is a signal that he believes Trump needs to pick a nonpolitician for such a sensitive post, not Cornyn.

If Trump takes McConnell’s advice, that would close off another door for Cornyn, leaving him with no soft landing in 2019. It wouldn’t be the first time a Republican whip was left off the leadership ladder.

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