This was hardly the missing 18 minutes of the Watergate tapes.

But for 18 minutes on Tuesday afternoon, someone, not something, was missing in Washington.

The Senate was scheduled to convene at 4 p.m. for a succinct session. But the confab didn’t start until 4:18 p.m. because the only senator required to be there to gavel the meeting in and out was running behind.

“I had a little trouble getting here,” said Sen. Rand Paul, R-Ky., as he hustled up a back staircase at the Capitol for the abbreviated session. Fox News is told traffic delayed Kentucky’s junior senator from arriving on time.

When Paul did arrive, he conferred briefly with Senate Parliamentarian Elizabeth MacDonough, then rapped an hourglass-shaped, ivory gavel on the desk, signaling the session started. The Kentucky Republican immediately asked the Senate reading clerk to announce a communication, which designated Paul as the senator authorized to preside.

The clerk no sooner finished reading the notice before the senator ended the encounter.

“Under the previous order, the Senate stands adjourned until 10 a.m. on August 26, 2016,” intoned Paul.

A pregnant pause ensued. From her seat on the rostrum, MacDonough wheeled around to clasp her hand on the ivory gavel. The gesture reminded Paul to tap it once against the desk to formally bring the assemblage to a close. The senator did so.

Thirty-four seconds in total, albeit 18 minutes late. Leave it to the United States Senate to take 18 minutes to do something that consumed a scant 34 seconds.

Yet holding a perfunctory meeting was of critical importance to Republicans.

The so-called “pro forma” sessions fall in the middle of the Senate’s seven-week congressional recess, and are simply “placeholders.” The Constitution requires both houses of Congress to convene every three days unless the other body blesses a recess. The House and Senate both approved an adjournment resolution which permitted the House to skate out of town, but not the Senate. The reason? If the Senate adjourned for more than 10 days and didn’t meet at regular intervals, it’s possible President Obama could make what’s called a “recess appointment” to the Supreme Court.

The president long ago tapped Merrick Garland to fill the vacancy created when Justice Antonin Scalia died in February. The Constitution allows presidents to bypass the Senate confirmation process for executive appointments if Congress is in the middle of a substantial adjournment. The Senate isn’t doing anything right now. But to at least align with the Constitution and “meet,” the GOP brass scheduled 15 cursory sessions between mid-July and early September to block a possible Garland recess appointment.

Thus, the imperative for Paul to come to the Senate’s drive-thru window Tuesday.

The Senate’s seen a few other minor issues when it comes to these pro forma sessions.

Sen. Mike Lee, R-Utah, was scheduled to preside over a pro forma session on July 22 immediately after the GOP convention in Cleveland. But travel issues prevented the Utah Republican from getting to Washington. Sen. Michael Crapo, R-Idaho, filled in for Lee. Sen. Tim Scott, R-S.C., was nominally late to preside over another recent session.

When Democrats ran the Senate in August 2008, then-Sen. Blanche Lincoln, D-Ark., was scheduled to preside. But Lincoln’s watch was running slow and she missed her turn to preside altogether. Instead, the Senate forged ahead with then-Secretary of the Senate Nancy Erickson presiding. A portion of Senate Rule I allows the Secretary of the Senate to wield the gavel in extreme circumstances. Sources tell Fox News that permitting Erickson to preside represented a misapplication of the rule and probably shouldn’t have happened. At the time, Democrats were orchestrating pro forma sessions to block then-President George W. Bush from making recess appointments. Sources tell Fox the Senate should have simply waited for Lincoln to materialize.

So the next Senate meeting is slated for Friday morning.

Various sources with whom Fox News consulted had no idea or wouldn’t say who would preside over that pro forma meeting.

“You’ll just have to wait to see who shows up,” chirped one source.

To say nothing of when.

Capitol Attitude is a weekly column written by members of the Fox News Capitol Hill team. Their articles take you inside the halls of Congress, and cover the spectrum of policy issues being introduced, debated and voted on there.