If President Obama's joint address to Congress did not make it clear that he intends to launch a bold new era of governmental activism, his ultra-ambitious budget leaves no doubt about it. For all the early concerns among liberals that he was reaching too hard for bipartisanship, the scope of his budget shouts his determination to turn the nation back toward core Democratic engagement across the board.

Taken as a package, the Obama budget is a huge gamble that he can capitalize on his current high public support, combined with the collective public fear over the financial crisis, to bring the real change he promised.

In his initiatives for universal healthcare, education, energy and environmental reform, Obama seeks not only to reverse the remnants of Reaganism. He also refutes the submissive Bill Clinton declaration in 1996 that "the era of big government is over."

The massive budget document confirms what conservative Republican leaders have feared and bemoaned — that the new president intends to make the pivot to activism in a range of areas under the cloak of responding to the immediate emergency on Wall Street and in the auto industry.

The negative outcry from the conservative wailing wall, led by the new self-proclaimed leader of the airwave naysayers, Rush Limbaugh, sets the stage for the resurrection of the lament of class warfare. Obama's pointed decision to end the tax breaks for the rich, a centerpiece of the Bush administration, assures that attack line from the right wing.

But the resistance will come not merely from the Limbaugh and other assorted ideological ditto heads. Every special interest whose ox would be gored under the Obama plan — the pharmaceutical and medical industries, the healthcare insurance business, the oil barons — will send their lobbyists into overtime on Capitol Hill to thwart various parts of it.

There have been optimistic references from the new president about halving the greatly enlarged federal deficit in his "first term." But there is little of the caution of a White House that has one eye on re-election, such as John F. Kennedy's restrained commitment to his civil-rights agenda in what turned out to be his abbreviated only term. Obama is laying it all on the line from the start.

In doing so, he can lose badly. But he also can deal a severe long-term blow to the Republican Party that so far is digging in to detour him. If he succeeds in bringing about economic recovery and also restores public confidence in activist government to deal with other challenges he has taken on, there will be little doubt of a second Obama term.

His conservative critics are already raising their standard laments against "social engineering" and "the redistribution of wealth." Can dire warnings of dreaded socialism be far behind?

Liberal Democrats are still unhappy. They don't like what they see as his low-balling of the issue that helped put him in office — his pledge to end the war in Iraq.

The reported slippage of his promise to get all American combat troops out in 16 months, to August of 2010, and particularly the retention of 50,000 U.S. forces in Iraq for protective and training functions, has not sat well with the Democratic congressional leaders.

So while Obama's budget gives Republicans on Capitol Hill plenty of reason to remain unified against him, he must cope with Democratic uneasiness about Iraq as well as the bombardment from the special-interest lobbyists bucking that budget.

In all, if the traditional honeymoon with Congress that a new president is supposed to enjoy survived his speech, his super-ambitious and many-faceted budget blueprint seems certain to make it a short one.

It's said that no president can achieve greatness in the absence of perilous times and the presence of national crises to measure his mettle. In all that Barack Obama has now set for himself to grapple with, the elements are certainly there to test him.

Reach Jules Witcover at (Unknown address).

Jules Witcover's latest book, on the Nixon-Agnew relationship, "Very Strange Bedfellows," has just been published by Public Affairs Press. Reach him at juleswitcover@earthlink.net.