Washington ? Barack Obama opened his presidency by drawing an unflinching portrait of the challenges. Then he set about turning those perils into possibilities.

In a dizzying dash to the 100-day mark, Obama made a down payment on the changes he’d promised and delivered a trillion-dollar wallop to wake up the moribund economy. He put the country on track to end one war, reorient another and redefine what it means to be a superpower.

All this with a cool confidence that has made more Americans hopeful that the country may at last be heading in the right direction.

The public couldn’t get enough of it, fixating on Team Obama’s every move: the arrival of family dog Bo; the president showing up for work in his shirt-sleeves; the first lady’s moxie in baring her arms; Sasha and Malia’s swing set; even a visit to the White House by the surviving Grateful Dead. Obama says it is a “weird fishbowl” that he has jumped into.

Not everyone’s impressed. For what went right with the president’s liftoff (after that small matter of the flubbed oath of office), his opening moves have fallen short in the eyes of many, and left others wondering where it will lead.

Republicans largely stiffed the president on his call for bipartisanship and cast him as a weak leader on the world stage. Liberals groused he could have done more and wondered whether he’s too prone to compromise. Deficit hawks worried he’s blown a gaping hole in the budget.

Obama himself seems energized. “The decision-making part of it,” he says, “actually comes pretty naturally.”

As for the critics, Obama says, Washington is “a little bit like ‘American Idol’ — but everybody is Simon Cowell.”

Almost overlooked in all the hoopla is the historic nature of Obama’s tenure as the first black president. There’s been little time to even think about that issue, which commanded so much attention during the campaign, as Obama has grappled with a seizing economy and has rushed pell-mell to reverse the legacy of eight years of Republican rule.

“You’d be hard put to find another president facing those kinds of challenges who has acted as intelligently and aggressively to meet the challenges head on,” said presidential historian Andrew Polsky, a professor at Hunter College in New York. “He hasn’t pushed things to the back burner. Of course, whether any of this works is another question, and it’s too soon to know that.”

Evidence of change

Change has arrived at a head-snapping rate, a product both of the troubled times and the president’s ambitious agenda.

There’s been the monstrous economic stimulus package that funneled billions into Obama priorities such as health care and renewable energy; a new law to provide 4 million more children with health insurance; another making it easier for workers to sue over discrimination on the job; the easing of Bush-era restraints on stem-cell research; jaw-dropping revelations about past interrogations; plans to put 21,000 more troops in Afghanistan; the White House-orchestrated ouster of General Motors Corp.’s top executive.

In smaller ways, too, evidence of change is everywhere. Obama was the first president to host a White House seder to mark Passover. His administration set aside tickets to the annual Easter Egg Roll for gay and lesbian parents. He was the first sitting president to do NBC’s “Tonight” show. His weekly radio address airs on YouTube.

There have been blunders along the way. It took three nominations for Obama to get his commerce secretary right, two to find a health secretary.