WASHINGTON, 1 May 2005 — For all the resolve and optimism that he projected in his news conference Thursday night, President Bush’s remarks represented a subtle midcourse correction after weeks of political turbulence that have depressed his approval rating and support for the Republican majority in Congress.

After devoting most of his energy this year to his proposal to restructure Social Security, Bush opened the session by expressing concern about rising gas prices. That responded to fears among some congressional Republicans that the party appeared out of touch with the kitchen-table concerns of most Americans while focusing in recent weeks on such issues as judicial appointments, the legal struggle over Terri Schiavo and even the long-term health of Social Security.

On Social Security, Bush executed another subtle shift in emphasis. After previously stressing his plan to carve out private investment accounts from the Social Security system, Bush focused Thursday on proposals to close the system’s long-term financing gap, even if he offered few details. That responded to the belief among many congressional Republicans that the best, and perhaps only, way to jump-start Bush’s plan on Capitol Hill is to shift the debate’s focus from private accounts to solvency.

On both fronts, it’s not clear that the initiatives Bush offered will change the difficult political dynamic facing him. He urged Congress to pass energy legislation by this summer, but acknowledged that it would have no effect on the high prices consumers confront at the pump today. And while he provided somewhat more detail on his plans to stabilize Social Security’s long-term financing, there were few signs the proposal would crack the unified Democratic resistance that has stymied his call for creating private investment accounts.

The rare prime-time news conference represented one of Bush’s most dramatic attempts to regain the initiative after a dreary spring of declining job approval ratings, rising economic anxiety keyed by soaring gas prices, continuing violence in Iraq and intensifying partisan hostility on Capitol Hill. Most national polls released in the last few days have shown his approval rating slipping below the critical 50 percent marker.

In the most recent CNN/USA Today/Gallup Poll, conducted April 18-21 and released last week, just 48 percent of Americans said they approved of his performance, while 49 percent disapproved.

That is the lowest approval rating Gallup has recorded for any president at this point in his second term since World War II — except for Richard M. Nixon in 1973, when he was under siege in the Watergate scandal. “Bush is not in a real good place right now,’’ said Alan Abramowitz, a political scientist at Emory University in Atlanta.

But none of that pressure was apparent Thursday. Bush was relaxed and frequently joked with reporters. Through 18 questions on subjects that included Social Security, Iraq and the political mood in Washington, the president appeared determined above all to project the two personal qualities that have served him best with his supporters: Resolve and optimism.

“I’m an optimistic fellow,’’ he said in response to a question about the economy, and that answer could have been his refrain for the evening.