Barack Obama will today mark the 100th day of his presidency after a whirlwind start in which he has signaled a new approach on policies from the economy to climate change to US relations with Iran.
Some have used the milestone to assess Mr Obama's policies, even as analysts cautioned it was too soon to say whether his long list of initiatives will yield success.
Underscoring the challenge the president still faces in pulling the country out of recession, new government data showed the economy contracted at 6.1 per cent in the first quarter, a steeper-than-expected pace, as exports sharply declined.
While dismissing the 100-day milestone as an artificial gauge created by the media, the White House is nonetheless putting a spotlight on it with high-profile events.
Those include a visit by Mr Obama to Arnold, Missouri, near St Louis, for a town hall event and a televised news conference at the White House.
The president, whose approval ratings are above 60 per cent, is trying to push his agenda for overhauling health care, fixing the troubled banking sector, rescuing US automobile companies, combating global warming and pursuing greater engagement abroad.
Looming large as well for Mr Obama is a flu outbreak that has presented him with his first public health emergency and a simmering controversy over his decision to release classified documents detailing harsh interrogations of terrorism suspects during the Bush administration.
Speaking at the meeting in Missouri, Mr Obama said al-Qaeda and the Taliban are the "single most direct threat" to US national security.
"In Afghanistan and neighboring Pakistan we do have real problems with the Taliban and al Qaeda," he said. "They are the single most direct threat to our national security interests. ... As commander in chief, it is my job to make sure that (Osama) bin Laden and his cronies are not able to create a safe haven within which they can kill another 3,000 Americans or more."
Giving a boost to Mr Obama's domestic agenda was the decision this week by Pennsylvania Senator Arlen Specter to leave the Republican Party and join the Democrats.
Senator Specter's move may put Mr Obama's party within reach of a crucial 60-seat majority in the Senate. That could make it easier for Mr Obama to pass some of his top initiatives, such as health care reform.
Appearing with Mr Specter at the White House just before flying to Missouri, Mr Obama said, "In these 100 days we have begun to move this nation in the right direction."
So far in his presidency, Mr Obama has enacted a $787 billion stimulus programme, launched a drive to overhaul the health care system, made overtures toward longtime US foes Iran and Cuba and unveiled new strategies for the Iraq and Afghanistan wars.
On the domestic policy side, Mr Obama has been criticised by some who contend the stimulus package and a proposed $3.55 trillion budget he laid out for 2010 will curb economic growth in the future by leading to a pileup of government debt.
Some critics have also faulted Mr Obama's handling of the banking crisis, saying he should have moved earlier and more aggressively to try to grapple with problem of bad debt hanging over the financial system.
But Mr Obama's supporters point to what they see as early signs his economic remedies may be working, including a steadier tone to the stock market and a stabilisation of new claims for jobless benefits after their prior huge increases.
The tradition of marking the first 100 days of US presidencies dates back to Franklin Delano Roosevelt, who trumpeted his ability to push through 15 pieces of major legislation in that time period after taking office in 1933 in the midst of the Great Depression.