WASHINGTON — Diplomacy now trumps defense as the main instrument of American foreign policy.

At least that is the intent that President Obama and his change-minded secretary of state, Hillary Rodham Clinton, spelled out on their first days. They made clear that the military will be a prominent — but no longer dominant — tool for achieving U.S. goals abroad.

The message was reflected clearly in Obama's decision, on his second full day in the White House, to close the military-run prison for suspected terrorists at Guantanamo Bay, Cuba, and to include the State Department in a broad government study of how to proceed with terrorist detentions in the future.

In a subtler but equally telling way, the commander in chief's decision to visit the State Department before stepping foot in the Pentagon indicated his intention to elevate the role of diplomacy.

Setting the stage for what amounted to Obama's first foreign policy address since his inauguration, Vice President Joe Biden told State Department employees on Thursday that Clinton's charter is to "put diplomacy back in the forefront of America's foreign policy," and to do so immediately.

"For too long, we've put the bulk of the burden, in my view, on our military," Biden said.

Obama put it this way: "A new era of American leadership is at hand, and the hard work has just begun. You are going to be at the front lines of engaging in that important work."

Biden didn't say so, but it will be difficult to bulk up the State Department's capacity for stronger diplomacy.

The reality is that the Defense Department is better equipped, with far bigger budgets, greater reach and a more committed constituency on Capitol Hill.

One measure of the disparity: The military has more band members than the State Department has diplomats. Or as Defense Secretary Robert Gates has noted, the 6,600 people in the foreign service equal roughly the number of personnel aboard a single U.S. Navy aircraft carrier strike group at sea.

Against that backdrop, Clinton's arrival at the State Department on Thursday was a feel-good moment for a diplomatic corps that felt neglected during the Bush administration. But she wasted no time warning all to temper their cheers with the sobering knowledge that the foreign policy road will be rough.

That includes not only the Guantanamo Bay headache but also others that the president and secretary of state will be confronting in the weeks ahead, from the stalled Israeli-Palestinian peace effort to nuclear dangers in Iran and North Korea.

Then there are the wars in Iraq and Afghanistan, where Obama has promised that diplomacy and perhaps development aid will play a more prominent role in seeking to stabilize those countries, not to mention the challenges of a rising China, an assertive Russia and a chaotic Horn of Africa.

Clinton also cited her pledge to reinvigorate the State Department by grabbing more resources, expanding the diplomatic corps, widening the role of development aid and building a civilian capacity to work alongside the military overseas.

Unconventional approaches will be much in demand. But Clinton seems determined to begin with basics, such as bigger budgets, reclaiming some of the clout that the State Department has ceded to the Pentagon in recent years, and restoring morale in an institution that has been derided as idle and placid.

In remarks Friday, Clinton lamented the migration of funds and authority from the State Department to the Pentagon. She noted that young officers in Iraq and Afghanistan are given millions in cash to spend as they see fit to build a school, open a health clinic or provide other nonmilitary aid.

"Our diplomats and our development experts have to go through miles of paperwork to spend 10 cents. It is not a sensible approach," she said.

Clinton has already shown some of the ways in which she will change direction at Foggy Bottom:

• Obama will include the State Department not only in meetings of the National Security Council but also the National Economic Council.

• She intends to make more use of special diplomatic envoys, in part to move the U.S. away from its recent practice of increasing the power of military commanders to interact with foreign leaders.

• She says she agrees with Gates that in fighting against Islamic extremism, military action should take a back seat to efforts to promote better governance, spur economic development and address the grievances among the discontented — roles tailor-made for the diplomats and development experts.