Look to Obama, soon, to walk back that July 2011 date and declare that any withdrawal of U.S. troops will be "conditions-based" -- another way of saying that if we are not winning the war in July 2011, we are not coming home.
Here is the likely scenario.
At the December review of the Afghan war, Petraeus will argue that, while progress is being made, we cannot meet our goals by July 2011. Years more of combat will be required to win the war.
Petraeus will ask the president for more time, perhaps years more, and perhaps ask for more troops, 20,000 or 30,000, to complete the mission and ensure Afghanistan is not again a sanctuary for al-Qaida.
Thus, in December 2010, Obama becomes LBJ in December 1967, when Gen. William Westmoreland, with 500,000 troops in Vietnam, came to the White House to ask for 200,000 more. LBJ said no.
And as the Republican right hammered him for not bombing Hanoi and blockading Haiphong, Sens. Eugene McCarthy and Robert Kennedy entered the primaries against him from the left.
Richard Nixon, saying five years of unsuccessful prosecution of a war called out for new leadership, was marching to the nomination of a party he had helped reunite after the Barry Goldwater disaster.
The outlook bleak, his party splintering, LBJ declared on March 31, 1968, that he would not run again.
If Obama repudiates his July 2011 date for first withdrawals of U.S. troops, if he agrees to any new Petraeus troop request, his party will split and he will face a primary challenge from the antiwar left.
But if he stands with Biden and says the July 2011 date holds, and the troops start home in July, Petraeus would likely put out word that his hands are being tied and he will not fight a no-win war.
Should Petraeus resign his command under such circumstances, he would become a Douglas MacArthur-like hero to the GOP, and could wind up as No. 2 on the ticket. And that could send Barack Obama home to Chicago.
Obama should have left McChrystal to succeed or fail with the McChrystal Plan. Had he succeeded, Obama also would have succeeded. Had he failed, Obama would have been free to relieve him and tell the nation: "We gave it our best shot, with our best general, with all the resources he requested. Regrettably, we did not succeed. Now we are coming home."
That option was closed when he fired McChrystal and made himself the political prisoner of Gen. David Petraeus.