Stephenson wrote it under the pseudonym “Stephen Bury”, and it can be found by that name in the US.
I’m more of a moderate, but I wasn’t a big fan of either book, particulary "Yellow Sausage Risi…"er, I mean, “The Bear and the Dragon”. It felt like he was trying to remake “Red Storm Rising” with a lot of Gratitious sex and the bit at the end felt a bit much.
I just finished Area 7 by Matthew Reilly. The President is a major character, as the rogue Air Force general is attempting to hunt him down in the super-secret base the aforementioned general took over just at the start of the President’s tour. And the President needs to put his hand on the Football every ninety minutes or the nuclear devices hidden in hangars in major American cities will all explode. And the tiny transmitter that the rogue general had installed in the President’s heart will send the activation codes if that heart stops beating. And the Chinese space shuttle is up to no good, as well as the unreconstructed South African commandos, and some of the rogue general’s men may be in it for themselves. And bears. But luckily, one of the Marines assigned to Marine One is “Scarecrow” Scofield, who recently survived the Antarctic incident…
The book I have on the boat for when I get bored also has a President as a major character. It is Balance of Power by James W. Huston. It was written in 1998, and is almost scarily prophethetic. An American merchant vessel is atacked by terrorists in Indonesia. The President is a lily-livered Ivy League liberal who actually protested against the Vietnam war AND visited Russia when he was a student. The President obviously is incapable of making the correct decision and tries to use the World Court and other lawyer tricks to get the terrorists, but the heroic Speaker of the House finds that Congress still has the power to issue Letters of Marque and Reprisal… That’s about as far as I’ve gotten in that book.
Damn. I read a lot of unmitigated crap…
The POTUS makes an appearance in The Mouse That Roared, by the late Leonard Wibberly.
HF Heard wrote a mystery story with the great title, “The President of the United States, Detective.” Alas, the story was only so-so, though it did postulate global warming when it was written back in 1947.
It’s funny that RealityChuck mentioned The President’s Plane Is Missing (which I haven’t read), because I highly recommend another book by the same author: Air Force One is Haunted. I planned to provide a link, but neither the hardcover, paperpack, nor mass market paperback seem to be available online (it was published in 1985 – when the Russians were still the bad guys). You might be able to get it from a library, but in the meantime here’s the back cover teaser:
It’s a good read, and a book that I reacquaint myself with every few years. 
(RealityChuck: is Jeremy Haines the President character in the other book, too?)
A check of Amazon reveals it’s now out of print, but back in 1977 William Safire wrote a trashy political thriller called Full Disclosure. It’s about the President surviving an assasination attempt, but being blinded in the process, and trying to keep the fact that he is blind secret.
The book sticks in my mind for one particularly memorable line. The President, who is divorced, has a girlfriend who comes over to the White House for sexual encounters from time to time. In the middle of performing oral sex on the POTUS, she says, “I’m going down in history!”