Good grief, Mr. President — just say "No."

To his aides, that was probably the best answer Donald Trump avoided giving when asked repeatedly if he had secret "tapes" of former FBI director James Comey.

Instead, the U.S. president played coy. He floated the possibility over 41 days that he recorded conversations with Comey, a rumour-stoking suggestion of his own making that steered him toward political self-harm, according to legal and political experts and former FBI officials.

Trump appeared to still be dropping hints earlier this month in the Rose Garden. When pressed by reporters about whether he possessed tapes, he teased them further: "Oh, you're going to be very disappointed when you hear the answer. Don't worry."

Finally on Thursday, Trump was unequivocal.

...whether there are "tapes" or recordings of my conversations with James Comey, but I did not make, and do not have, any such recordings. —@realDonaldTrump

"I did not make, and do not have, any such recordings," he wrote on Twitter, clarifying an earlier tweet on May 12 hinting that "James Comey better hope that there are no 'tapes' of our conversations."

That confirmation took long enough, as far as Paul Rosenzweig was concerned.

Senate intelligence committee vice-chair Democratic Senator Mark Warner, whose panel is investigating Russian interference in the 2016 election, speaks with reporters in Washington on Thursday. Responding to Trump's tweet, Warner said, 'This administration never ceases to amaze me.' (J. Scott Applewhite/Associated Press) Rosenzweig, who worked with special prosecutor Ken Starr during the investigation into the Clinton administration, thought the timing of Trump's admission missed the mark by weeks.

A growing mystery around what turned out to be non-existent tapes, he said, may have set in motion a cascade of damning congressional testimony, threats of subpoenas, unwelcome Watergate comparisons and an obstruction of justice investigation headed by special prosecutor Robert Mueller, himself a former FBI chief.

Mueller's appointment as a special counsel was "the collateral effect" of the president's loose talk about tapes, he said.

"If Trump winds up having caused the appointment of a special counsel to investigate him," he said, "it may go down as one of the greatest own goals in political history."

Were it not for Trump's innuendo about secret White House tapes of conversations involving Comey, the fired FBI director may not have felt compelled to come forward to leak memos giving his version of events leading up to his dismissal.

Chris Swecker, a former assistant director for the FBI's Criminal Division, said Comey would have had to be uncertain enough about the veracity of the president's initial tweet to feel he needed to testify before a Senate Intelligence committee.

His testimony corroborated Trump's account that the FBI director assured him three times he was not the focus of any investigations.

Trump 'may have successfully bluffed'

"It was well played, in a way," Swecker said of Trump. "I think he may have successfully bluffed that information out. I think he wanted Comey to come out and confirm that."

If that was a win, though, other revelations, including Comey's allegations Trump tried to derail an investigation into his national security adviser, raised potentially deeper concerns about possible obstruction of justice by the president. Those details were damning enough to make this a pyrrhic victory, Rosenzweig said.

"By bluffing him out on tapes that don't exist, you wound up getting 30 lawyers and maybe a $20-million investigation of your conduct," he said. "You've got to have rose-coloured glasses on to think the president is in a better place now than the day before he fired Jim Comey."

Democratic strategist Howard Franklin adds this to "another in a long list of self-inflicted wounds."

Audience members react as Trump speaks during a rally on Wednesday in Cedar Rapids, Iowa. Trump went nearly six weeks before saying he has no Comey recordings, (Charlie Neibergall/Associated Press) "How long can this administration intend to defy gravity? None of us really know yet."

The president's inner circle was reportedly not above lamenting their boss's response to the tapes controversy.

"If he doesn't regret this, he should," one Trump associate told CNN, calling the very suggestion that tapes existed in the first place "one of the worst things" he's wrought against his own presidency.

By refusing to settle the matter of the tapes earlier, Trump raised questions that never needed to be asked in the first place, said Ron Hosko, a former FBI assistant director who served under Comey and Mueller.

"Are there tapes? How do we get them? Do we compel delivery of the tapes? Do we go to court to get them?" Hosko said. "Now it looks like it's been a waste of a lot of people's time and energy."

One day before the deadline

Trump's statement came the day before a Friday deadline set by Congress to produce evidence of any tapes of his conversations with Comey. If Trump failed to submit them by then, he may have been subject to subpoena for those records.

Most politically damning in Hosko's mind is that Trump fed his detractors' beliefs about his administration being enmeshed in Watergate-like conspiracies. The last thing the president needed, Hosko said, was to hold up a mirror to Richard Nixon's scandal-ridden presidency.

'I struggle to see the logic'

"I think the Watergate comparisons are overblown," he said. "But why raise the spectre of Watergate and add another talking point to that discussion? I struggle to see the logic of why he says what he says."

Former House speaker and Trump loyalist Newt Gingrich chalked it up to instinct, telling The Associated Press it was the president's plan to "outbluff" Comey in a bid to "rattle" him.

If that was the intention, Hosko isn't sure how helpful it was, given that it may have led to the appointment of the seasoned, fair and tough Mueller to investigate Trump for obstruction of justice, something that would not have been a "joyous" development for the president.

"Maybe it was a strategy, maybe it was a reflex," Hosko said. "But after all this, I just don't see his tweet strategy as being an unmitigated success."