(Washington) President Barack Obama has tried to hold off debate on contentious social issues such as abortion, immigration and gay rights as he focuses on the economy and the wars in Iraq and Afghanistan. The Supreme Court vacancy will make that harder to do.

Political battles over new justices tend to center on those types of social issues far more than on economic and foreign affairs, which have dominated the opening months of Obama’s administration.

Some liberals have criticized Obama for postponing efforts to revamp immigration laws, protect access to abortion and allow gays to serve openly in the military. The president has taken the heat from his political base, hoping to avoid getting bogged down on a volatile issue early in his term, as President Bill Clinton did on the question of gays in the military.

The strategy has worked so far. Even the grumbling liberals are, on balance, happy to have Obama in the White House after eight years of Republican George W. Bush. And the economic distress has preoccupied Congress and the general public.

But the process to replace retiring Supreme Court Justice David Souter could pump new oxygen into national debates over abortion, immigration, minority rights, limits to privacy and other matters.

“There’s no doubt these debates are coming back,” said Matt Bennett, vice president of the centrist Democratic group Third Way. They might create more noise than suspense, he said, because there is little doubt that the Democratic-dominated Senate will confirm Obama’s eventual choice. Liberal activists will “fall in line” even if they are not entirely satisfied with the administration’s progress on their pet issues, Bennett said.

Obama has tried to push several of these social issues to the political background. At his news conference Wednesday, he said a bill important to abortion-rights advocates is not his highest priority. Access to abortion must be protected, he said, but “the most important thing we can do to tamp down some of the anger surrounding this issue is to focus on those areas that we can agree on.”

He was similarly noncommittal on immigration, which his aides see as one of the most difficult and emotional issues around. As a candidate, Obama said the nation must devise a way to help millions of illegal immigrants achieve legal status if they follow certain guidelines. But he has been mostly silent on the subject since his election. On Wednesday, he suggested he’s at the mercy of a slow-moving Congress, which has proved unable to agree about immigration for years.

“Ultimately, I don’t have control of the legislative calendar,” Obama said, “and so we’re going to work with legislative leaders to see what we can do.”

A Supreme Court nomination process threatens to amplify criticisms of Obama from liberals. Relatively few have added their voices so far to critics from the right. But those who have spoken out are likely to get more attention, and perhaps more support.

Some gay rights groups, for example, are unhappy that the administration is moving at a snail’s pace on efforts to replace the military’s “don’t ask, don’t tell” policy with one that lets gay people serve openly in the armed services.

Richard Socarides, a New York lawyer who advised Clinton on gay rights, wrote in Saturday’s Washington Post that Obama is erring by “waiting for some magical ‘right time’ to move boldly,” and now is “a uniquely opportune moment to act.”

Over a range of issues, Socarides wrote, “the Obama administration has shown a willingness to exploit this change moment to bring about dramatic reform. So why not on gay rights?”

On immigration, some mainstream Democratic activists have joined Latino groups in urging Obama to get the legislative process moving soon. Simon Rosenberg, president of the New Democrat Network, says there are several reasons to tackle the difficult issue this year. They include better pay scales for blue-collar workers if employers cannot exploit illegal immigrants, and better U.S. relations with Latin American countries.

Several liberal groups are dismayed that the Obama administration tried to block a lawsuit alleging that Bush broke the law when he authorized warrantless domestic spying on terrorism suspects. It was the second time that Obama officials, echoing the Bush administration, argued that the “state secrets privilege” trumped federal law in national security matters.

At his news conference Wednesday, Obama said he would like to change the state secrets privilege, but he asked for more time.

A Supreme Court confirmation battle, with televised Senate hearings, could energize liberal activists on all these fronts.

With Democrats now controlling the White House and Congress, conservative groups are almost certain to be loud and active in the upcoming debate. It might help them raise money, some Democrats say, but it won’t necessarily advance their political agenda.