Why wait the whole 100 days?

Barack Obama had barely taken office when cable channels began touting their coverage of "Obama's first 100 days." It was just 89 days into his term when the Los Angeles Times began its three-part assessment of those 100 days.

Similar pieces will flood the airwaves, Internet, newspapers and magazines in the next week, but it's an open question how valuable they can be.

The concept stems, of course, from the unprecedented way that Franklin D. Roosevelt reshaped the federal government during his first 100 days in 1933. The 100-day standard has been more systematically applied since Ronald Reagan sought to reverse the growth of government in 1981.

A review of those 100-day assessments suggests they tell us more about the president's style and intent than about his ultimate record.

There was no way to know after George W. Bush's first 100 days that his prime focus would be fighting global terrorism, rather than his initial emphasis on domestic issues. What was evident was that he was ignoring the minimal mandate of his disputed election and aggressively pushing a conservative social and economic agenda, starting with extensive tax cuts.

We also knew he was determined to compensate for his father's failure to win presidential re-election. What we didn't know was that his aggressive style and high-profile failures would make his more restrained father look good by comparison and severely hurt his party.

One thing that has had no predictive value is job approval. The recent president with the highest 100-day approval level, Ronald Reagan, and the lowest, Bill Clinton, both were re-elected. The average has been just above 60 percent, about where Obama is today.

Here are some things we knew -- and didn't know -- after the first 100 days:

Reagan: His was to be a "big issue" presidency, focusing on reversing the growth of government and aggressively countering the Soviet Union. There was no way to know his anti-Soviet stance would morph into a close relationship that produced arms reduction agreements -- or that the communist empire was nearing collapse.

George H.W. Bush: From the start, he stressed foreign policy, including a more bipartisan approach to Latin America and continued closer ties with the Soviet Union. His greatest successes were international: the 1991 Persian Gulf war and peaceful transition in Eastern Europe. There was no early hint of his reversal on a tax increase that alienated conservatives or of his failure to deal with recession, which undercut his initially bright re-election prospects.

Clinton: An inability to focus was evident early, as was his sloppy managerial style that led to a series of damaging flaps. Still, few imagined that personal scandal would prove nearly fatal in his second term. On the policy side, an early partisan tone gave little hint of the bipartisanship that later produced key achievements on welfare reform and budget policy.

Obama's first 100 days have revealed -- as his campaign promised -- an aggressive presidency seeking major policy changes while coping simultaneously with both the immediate economic crisis and its underlying problems. It's too early to know the extent to which he'll succeed or if he'll prove critics correct in judgments that he has overreached.

He's also shown an appealing, though somewhat aloof, personal style that has helped him hold support from the base that elected him but failed to offset policy differences with opponents.

Like Reagan, because of his successes, and George W. Bush, because of his failures, Obama's ambitious agenda stamps him as a potentially important president. Success could set the tone for a new era of Democratic domination; failure could open the way to a GOP comeback.