(CNN) When it comes to policy, President Donald Trump has a decent record of at least pursuing his core campaign promises. Obamacare is on the ropes. The US is on its way out of the Paris Climate deal. He has tried, over and again, to enact some kind of travel ban, first pitched as a blanket halt on Muslim immigration before being edited to block people from six Muslim-majority nations.

Where Trump falls curiously short, though, is in his day-to-day commitments. They'll come. It'll just be a few weeks, he says. But then the weeks drag on. The phenomenon isn't new, exactly, as his campaign was filled with empty threats -- the infamous "beans" were never spilled on Ted Cruz's wife -- and unfulfilled guarantees, like the press conference Trump said, in early August of 2016, Melania Trump would hold "over the next couple of weeks." It never came.

Trump carried this tic into the White House, where after five months in office, his habit of touting, then failing to deliver either timely policy proposals or evidence to back an assortment of claims, has become a recurring theme of his presidency.

Just a couple weeks now!

"We're going to be announcing something, I would say over the next two or three weeks, that will be phenomenal in terms of tax and developing our aviation infrastructure," Trump said on February 9. The actual outlines of a tax plan (cuts, not reform) didn't arrive until late April.

On June 5, he held an elaborate signing ceremony for the purpose of suggesting to Congress in a memo it move to privatize air traffic control.

To this day, no clear legislative text has emerged for either issue on Capitol Hill.

Funds to build "the wall" have been a budgetary nonstarter, despite Trump's claim at CPAC in late February that construction "is going to start soon, way ahead of schedule." He came closer to the mark on health care. The House unveiled the first edition of the AHCA on March 6, in the ballpark of what Trump promised on February 18, when he told supporters in Florida, "We are going to be submitting, in a couple of weeks, a great health care plan."

A second iteration of that bill, the deeply unpopular measure Trump himself called "mean" this week, passed the House on May 4. The Senate is now reworking it, under an unprecedented veil of secrecy, with no clear timeline for a vote.

Evidence coming... shortly

But many of Trump's most high profile dodges and delays have less to do with legislation than his untamed Twitter finger and the administration's subsequent clean-up efforts. The suggestion he was using a secret taping system inside the White House set off a chain of events that led Trump to claim last week that he was "100%" willing to testify, under oath, about his conversations with fired FBI director James Comey.

We'll see how Trump responds now if special counsel Robert Mueller comes calling, but it's hard to imagine he would -- especially with a private lawyer now on the case -- rush to offer sworn testimony. Meanwhile, those alleged "tapes" have been much longer in the offing -- and are, so far as they are real, very much Trump's to deliver. At his convenience.

Speculation over the nature of the would-be recordings began on May 12, when the President threatened his erstwhile FBI chief in a morning tweet.

"James Comey better hope that there are no 'tapes' of our conversations before he starts leaking to the press!", Trump said.

James Comey better hope that there are no "tapes" of our conversations before he starts leaking to the press! — Donald J. Trump (@realDonaldTrump) May 12, 2017

Terrible! Just found out that Obama had my "wires tapped" in Trump Tower just before the victory. Nothing found. This is McCarthyism! — Donald J. Trump (@realDonaldTrump) March 4, 2017

The "tapes" tweet echoed an earlier allegation, from March 4, when he alleged -- without any evidence -- that President Barack Obama "had my 'wires tapped' in Trump Tower" before the election. Despite repeated expressions of "confidence" that vindication was near, both by White House press secretary Sean Spicer and Trump, no proof was ever produced.

More recently, Trump and his top aides have been asked repeatedly about the Comey "tapes," and have, repeatedly, declined to provide a definitive answer as to whether or not they exist.

Asked by a reporter at his Monday briefing, Spicer punted again, saying that "the President made clear in the Rose Garden last week that he would have an announcement shortly."

Those comments, made during a joint news conference with Romanian President Klaus Iohannis, came last Friday. Asked on three times in the course of two separate exchanges, Trump first replied, "I'll tell you about that maybe sometime in the very near future," then, "I'll tell you about it over a very short period of time," and eventually, "Oh, you're going to be very disappointed when you hear the answer. Don't worry."

At this point, after all the hints and speculation, there is a precisely zero percent chance a real answer would be in any way "disappointing." Unfortunately, if past performance is any indication, Trump making good on his promise to tell seems about as likely.