In the past:

In the mid 1800's, the British and Russian governments were making sweeping advancements in Asia.  It didn't take long for the two European powers to get in each other's way, and subsequent conflicts broke out between the super powers.  This quasi-war became known as "the Great Game", focused on where the British held (of all places) Afghanistan as a buffer zone for India.  Holding onto this area became very unpopular with the British people as serious fighting broke out between the British army and the Afghani locals.  Therefore, the Liberal Party (today called the Labour Party) swept into parliament with the campaign pledge to move out of Afghanistan.  Upon taking power, however, they saw that removing troops would give the Russians an advantage, and therefore decided to go back on their promise for the good of the country.  The British stayed in Afghanistan for several years later in efforts to provide a counterbalance against the Russians, while holding onto their own ambitions.

Today:

The Democrats swept into congress two years ago riding on the assurance to end this war in Iraq.  However, Pelosi with the majority of other Democrats, have just voted for funding of this war for another full year (yet again).  Obama, campaigning to his base, has said that he would remove all combat troops from Iraq within 16 months of his administration.  Now that we are onto the general election, he has shifted his focus onto “listening to my generals” when he gets elected, and “refining my policy” after he visits the area here shortly.  This is not a flip-flop, but an obvious shift in focus that sparks serious thought.

In the future: (a prediction)

After defeating McCain, President Obama will not remove all combat troops within the 16 month deadline.  With the several successes that have come about with the surge, undermining this would be disastrous to his administration and assure his defeat at being reelected.  He realizes this, and continues to fight this out - to the utter consternation of the Moveon.org crowd.  Ultimately, pundits openly wonder if there was really any difference between McCain or Obama in terms of what either would have done in Iraq.  After all is said and done with all the campaigning and rhetoric, the President takes the responsible course of action, for the good of the country.