General David Petraeus is now in command of forces in Afghanistan.
He takes over after General Stanley McCrystal was fired and as U.S. troops suffer an increase in causalities.
The 130,000 troops in Afghanistan have a new leader.
"We are in this to win - that is our clear objective,” said Gen. Patraues.
General Petraeus formally assumed command of forces during a Sunday ceremony in Kabul.
He takes over from General Stanley McChrystal who was fired last week - after the General and his aides were quoted mocking the Obama administration.
Petraeus says - despite the change in command - the mission in Afghanistan remains the same.
"We must help Afghan leaders develop their security forces and governance capacity so that they can over time take over the task of securing their country and see to the needs of their people."
Petraeus takes over as U.S. causalities are on the rise and support for the nine-year-old war shrinks back home.
The General who led the surge in Iraq will try to accomplish the same in Afghanistan - but he only has a year before the White House plans to start bringing troops home.
Senator John McCain and his closest political allies think the July, 2011 deadline is a bad idea.
"Our commitment must be: we will succeed, and then we will withdraw,” said Sen. John McCain, republican from Arizona.
"We've got to win it. And therefore, you don't - you don't put that on a timeline,” said Sen. Joseph Lieberman, independent from Connecticut.
"If you send a signal to your enemies you're going to leave at a certain date, they'll wait until that date and wait you out,” said Sen. Lindsey Graham, republican from South Carolina.
Lawmakers may disagree about strategy - but most are united in their support for General Petraeus and believe he is America's best hope for winning this war.