Today’s presidential tracking poll from Rasmussen shows a two-point gain for Barack Obama, bringing him into a tie with Mitt Romney at 48/48. At first blush, that looks as though Obama may have righted the ship after the second debate, but Rasmussen warns that the most recent surveys show momentum in the opposite direction:

The Rasmussen Reports daily Presidential Tracking Poll for Friday shows Mitt Romney and President Obama each attracting support from 48% of voters nationwide. One percent (1%) prefers some other candidate, and another two percent (2%) are undecided. See daily tracking history. These updates are based upon nightly polling and reported on a three-day rolling average basis. As a result, roughly one-third of the interviews for today’s update were completed before Tuesday night’s presidential debate. In the two nights of polling conducted since the debate, Romney has a slight advantage. Tomorrow morning (Saturday) will be the first update based entirely upon interviews conducted after the second debate.

One has to know how tracking polls work in order to understand how Romney could be getting a bump while the overall number tracks the opposite direction. Today’s result dropped the surveying that took place the day before the debate, which apparently wasn’t terribly good for Obama, and retains the day of the debate, which apparently was better for the incumbent President, at least relative to Romney. The changes involved are relatively minor if one looks at the tracking history anyway.

However, Obama didn’t need to just trim Romney’s sails in that second debate. He needed an outright victory over the Republican challenger in order to reverse the momentum that now appears to be a preference cascade. And if Rasmussen is seeing improved standing for Romney in all three post-debate polls, Obama didn’t even achieve the sail-trimming objective.

That’s true with another Rasmussen poll released today. While the race in Virginia remains very close, Romney has now hit the 50% mark as most voters have settled on their choice:

Mitt Romney has now hit the 50% mark in Virginia. The latest Rasmussen Reports telephone survey of Likely Virginia Voters, taken two nights after the second presidential debate, shows Romney with 50% support to President Obama’s 47%. Two percent (2%) remain undecided. … A week ago, Romney led 49% to 47% in Virginia. Prior to this survey, the candidates have been within two points or less of each other in every survey here since April. Ninety-four percent (94%) of likely voters in the Old Dominion say they are certain to vote in this election. Among these voters, Romney leads 52% to 47%.

Romney is +3 with or without leaners. With leaners, het gets 49% of the independent vote to Obama’s 45%, and amazingly, wins both men (51/47) and women (50/47). Obama won Virginia in 2008 by six points, 53/47, while winning independents by one (49/48) but men and women by four and seven points, respectively. Rasmussen uses an R+2 sample, 32/34/33; 2008’s exit polling was D+6 (39/33/27), but 2009’s gubernatorial election was R+4 at 33/37/30. Independents ended up breaking 2-1 for the GOP in 2009, too — something to keep in mind when looking at late vote momentum.

If nothing else, one can assess at this point that the second presidential debate didn’t do anything to arrest Romney’s momentum — and that’s bad news for Obama as his foreign-policy position erodes ahead of the last debate on Monday.