The Campaign Spot

Dueling Iraq Plans: 50,000 Troops After 2010 vs. Less Than 70,000 by 2012?

Regarding the brouhaha of whether Iraqi Prime Minister Maliki has de facto endorsed Obama’s Iraq withdrawal plan… 
Recall that John McCain said that he expected that by 2012, “most” of the troops will be home from Iraq. By the end of the summer, the U.S. is slated to have 140,000 troops in Iraq. “Most”, it would be safe to say, would encompass more than half.
Insiders in Obama’s campaign suggest that his “residual force” that stays in Iraq to “target any remnants of al-Qaeda, protect remaining U.S. troops and officials and train Iraq’s security forces” could include as many as 50,000 troops.
Obviously, both campaigns will loathe the suggestion that there’s not much difference between their stands on one of the biggest issues in the campaign. But if McCain says that most of 140,000 will be leaving over the next four years, and Obama says that after 16 months the U.S. will be down to 50,000 troops in Iraq… aren’t we arguing about whether the U.S. should have about 50,000 troops in Iraq after 2010 or some number less than 70,000 by 2012? 
And at this point, isn’t the major difference is that one candidate has said that the speed of his withdrawal plan would be dependent on conditions and progress on the ground, and one hasn’t?