WASHINGTON -- President Obama's overhaul of the nation's health systems is unlikely to be completed by the White House's August deadline, lawmakers said Sunday as Congress turns its attention to other priorities.

Democrats and Republicans alike said the administration's sweeping health care proposals are moving forward on Capitol Hill but cautioned against rushing into a spending plan that could costs trillions of dollars over the next decade. Obama's health and human services secretary said she remains optimistic Congress would send the White House legislation before the year ends.

"I think everything is on the table and discussions are under way," HHS Secretary Kathleen Sebelius said.

But the White House's strategy to leave the legislative back-and-forth to Congress has produced varying and sometimes contradictory versions of health care legislation -- along with delays. As the Senate turns its attention to Supreme Court nominee Sonia Sotomayor's confirmation hearings, the focus will turn away from Obama's top domestic priority.

The administration's Democratic partners in Congress hinted they would not deliver legislation before leaving town for an August recess. Sen. Debbie Stabenow, D-Mich., said Obama should be pleased with lawmakers' progress; Sen. Kent Conrad, D-N.D., said "there really is plenty of time."

And Sen. Chuck Schumer, D-N.Y., insisted that lawmakers would have the overhaul in place before leaving town in August. He does not, however, expect Obama to sign it before lawmakers return to their home states.

The delay would be a blow to the White House and Democrats' electoral prospects.

The House and Senate are working toward legislation that would deliver on Obama's popular goals from his presidential campaign, but they are hardly in unison. House Democrats have proposed raising taxes on wealthy Americans to pay for the plan. Democratic leaders, meanwhile, have tried to calm moderate and conservative lawmakers about a proposal that could make their re-election bids more difficult.

Republicans, seizing on an issue that affects all Americans and has shown a glimmer for hope for an out-of-power political party, have lambasted the proposals as rash and irresponsible. They also see the issue as a way to win House and Senate seats in the 2010 midterm elections.

"I think the bigger issue here is why are we going to increase spending and health care by $1 trillion, $2 trillion, $3 trillion?" said Sen. Judd Gregg, R-N.H. "Most of which we can't afford, add that to the debt or add it the tax burden of the American people. Why don't we approach this horse from the other end?"

Gregg and other GOP leaders have painted the Democrats' plan as a government takeover of health care delivery systems that leads to rationing of treatment and backlogs at doctors' offices. More broadly, Republicans have tied the plan to out-of-control spending and a bloated federal government.

"There is no chance that it's going to be done by August," said Sen. Jon Kyl, R-Ariz. "President Obama was right about one thing: He said if it's not done quickly, it won't be done at all. Why did he say that? Because the longer it hangs out there, the more the American people are skeptical, anxious and even in opposition to it."

Sebelius tried to calm jittery voters who fear Democrats' plan to tax some employer-provided health care benefits as income. She said the details are far from over.

"Well, the House has a version," she said, discounting any version as final. "There are a couple of different proposals being worked on in the Senate."

Sebelius, Stabenow, Conrad and Gregg appeared on CNN's "State of the Union." Schumer appeared on NBC's "Meet the Press." Kyl appeared on ABC's "This Week."