CRAWFORD--The White House has torn up its familiar playbook and is embracing diplomacy in addressing some of its thorniest foreign policy challenges -- among them stalemate in Iraq and Iran -- in the waning months of George W. Bush's presidency.

Through seven-plus years of his presidency, Bush often has embraced a go-it-alone approach, digging in his heels even in the face of international disapproval.

Lately, however, the administration is showing a new-found flexibility as it attempts to rely more on its diplomatic hand as the president attempts to polish his legacy.

On Iran, Washington for the first time this week made overtures to a regime that it has had no relations with for more than two decades.

US envoy William Burns, undersecretary of state for political affairs, was in Geneva Saturday on a mission to bolster international demands for Tehran to suspend its controversial uranium enrichment program.

Attendance at the meeting by Burns -- the State Department's number three official -- marks a major policy shift by Washington, which has not had diplomatic relations with Iran since 1980 following the Islamic Revolution.

Talks in Geneva aimed to get Tehran to give up its disputed nuclear program in return for a package of incentives, although they ended Saturday without a deal.

Secretary of State Condoleezza Rice insisted that Tehran must suspend its enrichment and reprocessing of nuclear materials for substantive talks with Washington.

Rice added that the move represented "a strong signal to the entire world that we have been very serious about this diplomacy and we will remain very serious about this diplomacy."

US policy on North Korea also has received something of a makeover, with Rice announcing that she would this week visit Singapore, where she would take part in talks with her counterpart from Pyongyang for what could be the informal launch of the last stage of North Korea's denuclearization.

On Iraq meanwhile, the White House last week said Bush and Prime Minister Nuri al-Maliki have agreed after weeks of stalemate to set a "time horizon" for US troop withdrawals as part of a long-term security pact.

This breakthrough comes after months of White House insistence that it would not budge on the question of a timeframe for withdrawing US troops from Iraq.

"The leaders agreed on a common way forward to conclude these negotiations as soon as possible," White House spokeswoman Dana Perino said in a statement late last week, adding that the talks included discussion on "the resumption of Iraqi security control in their cities and provinces, and the further reduction of US combat forces from Iraq."

It was not clear however how deep the embrace of diplomacy is, or how long it will last.

White House spokesman Scott Stanzel said that little, in fact, has changed.

"The president has always believed that we don't want American troops in Iraq one day longer than they're needed," he said.

The New York Times in an editorial last week, praised the president's new-found flexibility, but questioned the depth of his commitment.

"We welcome Mr. Bush's willingness to try diplomacy for a change. But he might do even better if he didn’t trumpet his ambivalence quite so loudly."

Meanwhile, Graham Allison, a security expert who teaches at Harvard University, suggested that the administration's recent readiness to talk could be a prelude to a return to a reliance on military solution to some of Washington's intractable foreign policy problems.

"The hard-liners in the Bush administration, for example, will do their best to insist on unachievable objectives that will ensure failure of negotiation," he said.

"If talks collapse, they will be able to argue that the US went the extra mile and exhausted all reasonable alternatives" leaving the military option squarely on the table, he said.