My bet is that Obama suffers a 3% drop in support as voters who supported him on principle resort to a second level issue to make a distinction and cast a vote.

From what I gathered on the primaries I see that 15% to 18% of voters decided the candidate of their parties.

I saw that the GOP had a steady 3 to 5 % turnout for Ron Paul, independents and "principled" voters, similarily the numbers at Obama website indicate 2% of the total; 20 thousand protesting.

My point is this, that those who would take a principled stand against FISA and amnesty, and after immunity is granted, will make a next level decision or second tier decision of support.

It might be based on smaller government, gun rights, or other rather libertarian ideals, but with the FISA issue off the table, easily a 5 percent shift could occur.

Meanwhile, the McCain campaign is already using Obama's FISA flip-flop to attack the senator.

"Over the past several weeks, Barack Obama has made it increasingly difficult to take him at his word on anything," wrote John McCain's senior policy advisor Doug Holtz-Eakin in a memo sent out to the press Monday morning. "After pledging to accept public financing, he decided not to. After saying he would debate 'anywhere, anytime,' he decided against participating in any of the 10 joint town hall meetings.  After backing the D.C. handgun ban, he now says it was unconstitutional. After pledging to filibuster the FISA bill, he voted for it."

The real point is that Obama has been caught in a circumstance where he can't flip-flop out of the flip-flop he is in.

My bet is that the moderate, libertarian, and independent voter evaluates the support differently after this vote, and I bet that McCain and his campaign will find ample opportunities to point out that they must vote in the absence of this FISA distinction within the choice.

Arguing that those votes will go third party is not wise, asked to evaluate who has a legacy with this independent voter segment from 2000, and who has been historically more sympathetic to libertarian ideals, Obama painted as big-government flip flopper was the one break McCain needed as an issue as a summer wears on.

It has not been a kind year for the favorites, Obama made that trend easier by allienating voters who supported him on the "FISA principle of no immunity" and the people who care about this issue don't equate "principles" with "compromise."

Repeating "Flip-Flop" and "compromising principles promised" makes the McCain message easier.

This issue this fall, can make big states close if Obama cannot close the deal with Catholics and Independents.

A principled stand on FISA was one of the few wedge issues that Obama had with libertarians and independents.

He now no longer has it and McCain will not allow the voter to forget it.

It was a mistake that I'll come back to as the election nears to a conclusion.