This review may contain some spoilers, but I use that term loosely, as I won't actually be "spoiling" anything for you. Trust me, I'm doing you a favor by telling you what happens. Just spare yourself the 2 hours needed to actually watch the film.
OHF was just a complete crap fest. Butler was actually serviceable as the hero. But if you want to see him in a decent performance in an actually decent film, try "Law Abiding Citizen," which ironically also features Jamie Foxx, who was in "the other White House movie." Once you get past Butler, there's pretty much nothing redeeming about this movie. Dylan McDermott plays a fellow Secret Service operative who ends up being the token traitor, as he sells out to the North Korean terrorists who take over the Washington D.C. landmark. There is never a clear motive established for his character having wanted to harm the President or his country. Yeah, there's the money factor, but shouldn't we assume it would take a little more than that to turn an operative whose sole job it's been to PREVENT the President from getting hurt?
The sort of MacGuffin of the film (an object that one or more of the characters spends the majority of the film trying to obtain) are the "Cerberus Codes." It's explained that these were a set of three codes...one in possession of the Chairman of the Joint Chiefs, one held by the Secretary of Defense (Leo), and one by the President, that when entered into the computer (conveniently located in the White House bunker where all three of those people were being held hostage), would basically give access to and control of the United States' nuclear arsenal. The North Korean villain started to torture both the Chairman and the Secretary to get their codes, but the President (Eckhart) ordered them both to give up the codes, insisting that he would never give up his, so they would be useless to the terrorist.
The evil Kang's plan to subvert this ploy by the President, was to capture his young son, knowing that the threat of harm to the kid would break the President and lead him to surrendering the final code. However, the very next thing that happens is the kid rescued by Agent Mike Banning (Butler), and everyone in the bunker finds out that he is safe. Then, for some reason that can't possibly be explained, Kang is able to obtain the third code from the President anyway. Completely nonsensical. To add to the mystifying actions by the characters in this film, the Speaker of the House (Freeman), who is now the acting President, since the Vice President is also being held in the bunker, caves into Kang's demand that the US start withdrawing all of its troops from the North/South Korea border. THEY'VE ALREADY RESCUED THE PRESIDENT'S SON and supposedly thwarted Kang's entire plan, so why would he possibly make this decision?
Of course, Agent Banning ends up shutting down the Cerberus system as the "clock" ticks down to its final seconds...a tired and predictable action movie sequence. And then, he kills Kang in one of the most boring villain kill scenes I can remember.
Overall, this film was a waste of everyone's considerable talent. Hard to believe they assembled a cast and director like this and got these results. Even more incomprehensible is...THERE'S GOING TO BE A SEQUEL!! "London Has Fallen" is due out next year, and almost everyone except Fuqua is returning. Yeah people...no thanks!