The hyped birther reversal and implied Q&A the press was so breathless to capture was obviously a total sham and shameless manipulation of the fourth estate to advance Trump's interests. The interesting thing is that it wasn't really a convincing repudiation of his birther beliefs and seems to have been staged so as to subtly reinforce them. By playing a prank on the press to show that he can dominate and outfox reporters, showing everyone how gullible the press is, and then drily pronouncing the prescribed words as a parting shot in a long self-promotional event, he did just the opposite. "See, they wanted me to say it and I said it, so there. No further comment." (If they fell for the fake press conference, they'll also swallow a pro-forma acknowledgement of Obama's birth in the U.S. and drop the issue. Both are equally insincere.)
This is a 180-degree dog whistle: it doesn't hint at covert support for a horribly extreme version of an ostensibly normal-sounding position; he says the exact opposite of what he means, knowing full well his hardest-core base will understand. Denying a Democratic president's legitimacy continues to be helpful as ambient noise, but this particular message no longer serves a practical purpose and can be discarded as a distraction from focusing on how Clinton is illegitimate. (All Democrats are illegitimate to the most deplorable elements of his base, it's just a question of how.)
Besides his humiliation of the press, we know that his statement was disingenuous also because of the cast of characters he invited to join him. He was introduced by a birther hero and surrounded by military kooks who are no doubt fervent birther (and other types of) conspiracy theorists themselves. That's a clear wink to his base that deep-down his views have not changed, he's just doing what's expedient to placate the stupid, loathed press, while also getting its goat as a revered master trickster.
A person sincerely reversing a long-held position might explain how he came to hold the view in the first place and what made him change his mind, explain why the President clearly is and always has been an American citizen and fully eligible to hold his office. Since the claim was insulting, one would expect an apology to the President. (Not to mention that the lowest dregs of Obama-despisers depict him as sub-human and not just technically not an American citizen.*) Since he now understands bitherism to be false, one would also expect an apology to the people who believed the erroneous information. He could be expected to make an effort to convince people to change their views on the President's legitimacy. (I'm pretty sure that if a poll were taken now asking Trump supporters whether 1) they previously held a birther stance, 2) saw or heard about Trump's statement, and 3) now believe Obama was born in Hawaii, the numbers would not be much different from where they were before. An interesting fourth question might be whether they think Trump really has changed his position or was just doing what he needed to do politically. I hope someone executes this poll just out of curiosity.)
However, the biggest coup in this is perhaps that people in the press, like me, continue to indignantly fixate on the micro, manufactured news items served up by a salesman and a team of experienced propagandists and overlook the macro issues throbbing in plain sight. There is little time left before a historic election with serious ramifications, and the reporters and pundits might consider ceasing to stroking their corporate beards and wondering what it all means and zero in on the important issues for voters (the country's last hope to avert this disaster, it’s all on us). Our democracy is in crisis, and it is crass and unethical to worry about profits and careers at a time like this.
*I continue to marvel at how classy the Obamas are in the face of this steady drumbeat of calumny. I wish there were some sort of award for this.