Tom Bowman

The violence against U.S. forces in Afghanistan has called into question the American exit strategy, which is set to play out steadily over the next three years.

It was only a few weeks ago that the second-ranking American military officer in Afghanistan laid out a new phase of that strategy. Small groups of U.S. advisers would team up with larger Afghan units to train them, said Lt. Gen. Curtis Scaparrotti.

The first of these U. S. assistance teams will head into Afghanistan this spring to train Afghan police and soldiers.

At the White House on Tuesday, President Obama greeted China's Vice President Xi Jinping and called for cooperation between the two nations.

Later in the day, the Chinese vice president crossed the Potomac to visit the Pentagon, where the U-S military may hope for cooperation, but has to plan for possible confrontation.

The Pentagon's new budget request, unveiled Monday, signals a shift for the US military, with a greater focus on the Pacific.

China is building more ships and aircraft, and is now patrolling hundreds of miles out into the Pacific.

American commanders in Afghanistan are preparing for a major shift in their mission this year.

U.S. troops are expected to move away from their lead role in combat operations in most areas. Instead, they'll advise Afghan forces to take the lead in both operations and security duties throughout much of Afghanistan.

The nation's top military officer, Gen. Martin Dempsey, is in Israel where he's expected to send a clear message: Don't attack Iran and let the tougher sanctions take hold.

Gen. Dempsey's trip to Israel was scheduled weeks ago, but it comes at a particularly sensitive time. Iran has threatened to close the Strait of Hormuz, the key route for oil shipments, and has stepped up its naval activities.

An Iranian nuclear scientist was recently killed by a drive-by assassin, and Iran is blaming Israel.

As tensions rise between Iran and the West, Tehran has threatened to block the Strait of Hormuz, a transit route for one-fifth of the world's oil. Is it more than an empty threat?

"The simple answer is: Yes, they can block it," Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, said on CBS's Face the Nation on Jan. 8.

"They've invested in capabilities that for a short period of time block the Strait of Hormuz," he said.

Thursday, the Pentagon announced its new strategy for dealing with threats around the world. The goal is to use the new blueprint to guide difficult budget choices in the coming years. The new document is released as the U.S. winds down two long wars — in Iraq and Afghanistan — and embarks on a period of defense budget cuts.

For two decades, the Pentagon has maintained that it could fight two wars at the same time. But as the Obama administration releases its new military strategy Thursday, some question whether the Pentagon will abandon that long-held commitment.

An early draft of the Pentagon's new strategy, The New York Times reported, said the military would only be able to win one war and spoil an adversary's efforts in a second war.

One of the more controversial episodes of the Iraq war will be revisited in a military courtroom in California this week.

In November of 2005, a Marine squad killed 24 Iraqis, some of them women and children in the village of Haditha. Staff Sgt. Frank Wuterich led the squad of Marines, and on Wednesday he'll face voluntary manslaughter charges at Camp Pendleton.

The U.S. troops have left Iraq, and U.S. diplomats will now be the face of America in a country that remains extremely volatile.

The U.S. Embassy in Baghdad, along with several consulates, will have some 15,000 workers, making it the largest U.S. diplomatic operation abroad. Those diplomats will be protected by a private army consisting of as many as 5,000 security contractors who will carry assault weapons and fly armed helicopters.

Here's the conventional wisdom about the U.S. troop surge in Iraq: By 2006, Iraq was in chaos. Many Americans called for the U.S. to get out. Instead, President Bush sent in 30,000 additional troops. By the end of 2007, Iraq started to stabilize, and the move took on an almost mythic status.

In 2008, for example, Sen. Lindsey Graham spoke at the Republican National Convention about the U.S. presence in Iraq, saying that, "by every measure, the surge of troops into Iraq has worked."