Mark Warner’s the ranking member on the Committee, not the chairman, so it’s not his decision to make. That belongs to Republican Richard Burr. Would Burr defy partisan interests to demand recordings Trump made of his chats with Comey?

“There’s no simple mechanism, but you can be sure we’ll take a look at it,” [a] committee aide said…

The Senate Intelligence Committee ― which is also probing connections between the Trump team and Russian officials ― does not necessarily need to have proof that the tapes exist in order to subpoena them, Bradley Moss, a national security lawyer, told HuffPost. Senate investigators could ask for “any recording devices or backup copies that were referenced in the post made by President Trump on the morning of May 12, with respect to recordings with President Trump and Director Comey,” said Moss.

Three threshold questions. One: Was it legal for Trump to record Comey secretly? Pretty clearly, the answer is yes. Two: If Trump did record Comey, would it be legal to now destroy the recordings? Possibly not, no:

If Trump is actually taping convos, the Pres Records Act requires they be archived, and would violate criminal law (18USC641) to delete them

— Daniel Jacobson (@Dan_F_Jacobson) May 12, 2017

Three, the big one: Do tapes exist? Only Trump and the inner circle know for sure but he’s had a reputation for secretly recording conversations for years. Three “former high-level employees” of Trump’s during the past 30 years told the Wall Street Journal they had “direct knowledge” of him taping phone chats and even saw “devices” used for that purpose. (“He recorded virtually everything in the office.”) Four former employees at Mar-a-Lago told BuzzFeed last year that Trump had a sort of “switchboard” in his room there that allowed him to listen in on phone conversations on other landlines in the building(!). Trump’s spokesman and two other Mar-a-Lago employees denied that, but another BuzzFeed report from 2016 claimed that Trump used surveillance equipment extensively throughout his home in suburban Virginia and the nearby Trump National Golf Club, far above and beyond what you’d expect even for luxe properties owned by a billionaire.

Whom to believe? Well, here’s an amazing anecdote via WaPo of an interview its reporters did with Trump last year:

Last spring, when two Post reporters visited Trump in his office for another interview, Trump, in the middle of telling a story about how he demolished the Manhattan landmark that had stood where Trump Tower is now, asked his guests if they would like something to drink.

In the same quiet voice in which he’d been conducting the interview, Trump said, “Okay, two waters and a Coke.” The interview resumed and less than a minute later, a secretary walked in with the drinks. No one other than the reporters and Trump had been in the office. And Trump never signaled the drink request to anyone outside the office.

Odds that tapes exist: Fair to high. Maybe the best answer to the question is another question — if tapes didn’t exist, wouldn’t Sean Spicer have said so forthrightly when asked about it on Friday?

There’s another important question lurking. If the Senate Intelligence Committee subpoenas the tapes, could Trump quash the subpoena as an infringement on separation of powers? SCOTUS refused to let Richard Nixon do so during Watergate, but that case differed — for now — in potentially crucial ways. The subpoena in Nixon’s case was issued as part of a criminal trial, not a congressional inquiry, and the Court’s ruling noted that the president sought to defy it “not on the ground that military or diplomatic secrets are implicated, but merely on the ground of a generalized interest in confidentiality.” Presumably a recording of Trump and Comey could be redacted to remove any discussion of state secrets before the rest of the tape is turned over, but does the president have a duty to comply with Congress in the first place? That could be a long court battle.

I’m sure Democrats don’t mind, though. The beauty of Friday’s presidential tweet about “tapes” from the left’s perspective is that, at a minimum, it’s a sweet wedge against Trump and the GOP and a nice motivator for their base in the midterms. Warner can make Burr squirm by calling for a subpoena publicly while vowing that if voters give his party control of the Senate next year, he’ll reward them with a presidential subpoena even if Burr refuses. Trump handed them a club to use on the GOP, and not for the first time. Here’s Warner talking subpoenas and the prospect of Jim Comey testifying — publicly — about the president.

.@MarkWarner says he will "absolutely" subpoena White House tapes; if they exist, we need to make sure they don't "mysteriously disappear." pic.twitter.com/dPngKUfGzZ

— This Week (@ThisWeekABC) May 14, 2017

.@MarkWarner: "We would love to have Director Comey appear at an open hearing," he deserves his chance "to lay out his side of the facts." pic.twitter.com/oSOxbnQjEC

— This Week (@ThisWeekABC) May 14, 2017