WASHINGTON -- On the eve of his 100th day in office, Obama received what may have been the best "anniversary" present a president can get: a high-level defection in Congress to his political party by a member of the opposition.
Seventy-nine-year-old Arlen Specter of Pennsylvania has spent nearly 30 years as a Republican senator. But on April 28 he announced that he was switching his party allegiance to the Democratic Party.
Specter's decision puts Democrats in the Senate within one vote of having a "super majority" of 60 -- enough members to stop Republicans from blocking passage of legislation through a filibuster. (The 60th non-Republican seat is expected to come later this spring with the resolution of a disputed election in the state of Minnesota.)
At a press conference, Specter insisted that he will maintain his independent judgment and not automatically become the Senate Democrats' "60th vote," but his defection has already given Democrats a boost of confidence.
Specter's former Republican colleagues have already accused him of bald-faced opportunism, citing figures to suggest he faced an uphill climb in their party's primary ahead of the 2010 election.
Whatever his motivation, the White House said Obama "was thrilled" by the news.
As with any assessment of a U.S. administration at such an early stage, particularly one with such an ambitiously defined domestic agenda, there is a risk of commentators confusing a momentary upper hand with broader presidential success.
Most observers would agree that at the 100-day mark, it would have been nearly impossible to forecast the issues that will eventually define the presidency of Obama's predecessor, George W. Bush.
Democrat Jimmy Carter was the last U.S. president to have a filibuster-proof majority in the Senate, during the first two years of what was destined to remain a one-term presidency.Instilling Optimism
But the new president has other reasons than the Specter defection to be happy as he marks the 100-day milestone. New polls show that an overwhelming majority of Americans -- nearly 70 percent -- approve of the job he's done so far in Washington, according to an ABC News/Washington Post poll on April 21-24.
Unemployed Americans at a job fair in Los Angeles in mid-March
Statistics don't necessarily explain such optimism. Unemployment figures and the stock-market levels, for instance, are largely unchanged from three months ago.
But opinion polls seem to reflect a belief that things are starting to turn around. If there's one message Obama has tried to send during his first months in office, it's that Americans have the strength and the spirit to recover from this economic crisis. In persuading the country of that, he has largely succeeded in the short term.
On the domestic front, Obama's biggest achievement so far has been to convince Congress to pass the biggest peacetime economic stimulus plan in history. The $787 billion "American Recovery and Reinvestment Act" is aimed at creating millions of jobs and rebuilding America's infrastructure.
John Judis, who is a scholar at Washington's Carnegie International Endowment for International Peace and a senior editor at the liberal-leaning magazine "The New Republic," says Obama has created a sense that "history is moving inexorably" in the right direction.
Obama's critics say the stimulus plan was too costly, relies too heavily on government spending as opposed to tax cuts, and will fail to bring early results.
Judis, who has covered U.S. presidents since 1976, disagrees, and argues that Obama's fiscal plan was the right decision for the country.
"I like the budget a lot," Judis says. "I think it combines both a stimulus program and revival of American industry. Things like renovating the [railroad system] [and] extending Internet broadband to rural areas. Things like that are important to the future of the American economy."Bruising Battles
The list of domestic policy changes effected by Obama is already long. The most notable came just hours into his presidency: a decision to shut down the military detention center at Guantanamo Bay and to end interrogation techniques considered to constitute torture.
Others major changes include the regulation of emissions thought to cause climate change, a lifting of the ban on medical stem-cell research, and an extension of health care for poor children.
Obama's first three months have not been without their setbacks. Three of his Cabinet nominees have withdrawn their nominations -- including former South Dakota Senator Tom Daschle, whom Obama had picked to lead flagship health-care reforms -- and at least six presidential appointees were discovered to have embarrassing personal tax issues.
When the public learned that some of the executives of the financial institutions that received government bailout funds had been given multimillion-dollar performance bonuses, Obama was accused of not doing enough to stop them.
Chief executives from major banks and financial institutions that received bailout money testify in Congress in mid-February.
His handling of TARP, also known as the Wall Street bailout, continues to come in for criticism for failing to restore confidence to the financial markets.
Obama was expected to mark his 100th day in office with a primetime news conference that most national television stations will broadcast live.
When he takes the podium, it's likely he'll be thinking about the next major political signpost of his presidency: November 2010's Congressional elections.