WASHINGTON — Henry Paulson, a veteran of more than three decades of Wall Street booms and busts, knew the good times couldn't last forever when he left his perch as head of Goldman Sachs two years ago to become President Bush's third Treasury secretary.

He just didn't know yet what form the downturn would take.

"I didn't realize I would have to learn so much about housing," Paulson said in an interview in his office at the Treasury Department, just steps from the White House. But, he added, "the possibility that I might be sitting here in the middle of all this didn't seem that unlikely to me."

Now, 10 months into housing and credit crises that are reverberating across financial markets and the broader economy, Paulson faces a long list of complicated economic problems. The dollar is extremely weak, oil prices are very high and, with home prices tumbling, foreclosure rates are spiking. Plus, Wall Street is reeling from its exposure to home-loan defaults, as evidenced this week by Lehman Brothers' decision to oust two top executives and raise $6 billion to offset its mortgage market risks.

Paulson's imprint on the Bush administration's response is clear. He was pivotal in negotiating the $168 billion economic stimulus package with lawmakers from both parties and played a key role in brokering the Federal Reserve-backed purchase of the troubled investment bank Bear Stearns by J.P. Morgan.

Yet to be seen is how history will judge these interventions.

The jury is out, for example, on whether the rebate checks sent to taxpayers — the cornerstone of the stimulus plan — will spur enough consumer spending to head off a recession. And while the Bear Stearns rescue may have prevented a potentially destabilizing collapse, the deal has some economists worried that the government may have encouraged more unhealthy risk-taking down the road by not allowing the investment bank to fail.

At the same time, Democrats complain that Paulson and the Bush White House are not doing enough to stem the tide of mortgage foreclosures and keep more Americans in their homes.

Mark Zandi, chief economist at Moody's www.Economy.com, believes the government had little choice but to put taxpayer money on the line for the Bear Stearns buyout. Yet he sees inconsistencies in the administration's unwillingness to do the same thing to help distressed homeowners.

Roger Porter, a Harvard University professor and former economic adviser in several Republican administrations, gives Paulson credit for playing a difficult hand well.

"Henry Paulson has skillfully and competently managed the situation he inherited," Porter said. He added, however, that it is too soon to know how successful Paulson will be in pushing his own longer-term priorities. One top priority, a sweeping overhaul of financial services regulations, has gained little traction.

Yet, even as he confronts the current turmoil, Paulson continues to press ahead with his plan to streamline regulation of the financial services sector. Among other things, his plan would expand the Fed's authority to oversee the financial markets and merge the federal agencies that supervise the securities and commodities futures markets.

Some have assailed the blueprint as an attempt to push through broad deregulation in the midst of an economic crisis that resulted from too little oversight. Critics are particularly concerned that the plan would weaken the Securities and Exchange Commission, which serves as a watchdog over Wall Street.

For his part, Paulson said the proposal does not aim to either expand or reduce regulation, but to update an antiquated system. He added that after all the Wall Street excesses he has witnessed over the years, he sees an important role for regulation and investor protection.

Although the blueprint stands little chance of passage before Bush leaves office, Paulson hopes it will shape the debate for the next administration.

For now, though, his top focus is stabilizing the economy.

"I've been taught to run to problems, rather than run away from them," he said. "I'll do my best right until I leave."