President Donald Trump is calling on Republicans to be the party of health care . But that's not going to be so easy to do since it requires them to have a plan.

"The President, I don't think, really has any idea what he's really saying there. It's more of a promotional and marketing impulse on his part," said James Capretta, a health care expert at the American Enterprise Institute, a free market think tank. "It leaves Republicans open to a little bit more attacks and ridicule by the Democrats that they don't have a plan."

While the party hasn't coalesced behind a health care plan, there are policies that Republicans have long supported. Yet some Republican think tanks, particularly the influential Heritage Foundation, are looking to drum up interest on Capitol Hill in their ideas to overhaul the health care system.

Some are still pushing a version of a 2017 bill from Sens. Lindsay Graham of South Carolina and Bill Cassidy of Louisiana to replace the Affordable Care Act.

The senators unveiled the legislation just before the GOP repeal effort collapsed for good in 2017. It would turn the federal funding for Medicaid expansion and Obamacare's subsidies for premiums and out-of-pocket costs into a block grant program. States would receive a lump sum of money and would have a lot of leeway over how to spend it.

The bill would also let states alter several key Obamacare protections for those with pre-existing conditions. While it would still require insurers to provide coverage to everyone, states could adjust other rules, including the mandate that insurers offer comprehensive policies.

Also, states could change the pricing rules so that younger, healthier people could see their premiums go down, but those who need care and older Americans in their 50s and 60s could find themselves unable to afford policies.

States could also revamp many of Obamacare's financial protections, including limiting how much people must pay out of pocket each year and how much of the tab insurers must pick up.

While Trump is enamored of the plan and incorporated it into his budget, it's not likely to get far in the Senate. Asked whether Congress could come together on a replacement plan, Graham told CNN's Kate Bolduan Wednesday that he doubts it.

Revamping the nation's health care system isn't exactly the GOP's strong suit. The party failed spectacularly to repeal and replace the Affordable Care Act in 2017 when it dominated Washington. The task will be only harder now that Democrats control the House and are pushing plans to strengthen Obamacare and protections for those with pre-existing conditions, likely a sharp contrast to whatever proposals or talking points Republicans roll out.

Key GOP senators also haven't expressed much appetite for going into full-scale battle again over the Affordable Care Act. Asked about health care, Sen. Chuck Grassley of Iowa on Wednesday pointed to his finance committee's work on lowering prescription drug prices. He is collaborating on that effort with Ranking Member Ron Wyden of Oregon.

"Most of it's going to be very, very bipartisan," Grassley said of his committee's plans on health care.

Sen. Roy Blunt of Missouri said he will let the Trump administration take the lead.

"All I'm going to say about that for a while is that I'm eager to see what the administration proposes," he said Wednesday.

The Trump administration, however, is not waiting for Congress to change the health care system, particularly Obamacare. Its strategy centers on letting states overhaul their health programs. For instance, it has allowed states to implement work requirements in its Medicaid program and is now considering requests to let states expand coverage only to those below the poverty line.

Officials have also made it easier to buy short-term plans that have lower premiums but don't have to adhere to all of Obamacare's rules. And they are looking to let states alter their Affordable Care Act programs, including allowing them to funnel subsidies to people buying coverage outside the exchanges.

Meanwhile, a coalition of conservative groups and several GOP state representatives last year rolled out the Health Care Choices Proposal, which includes giving states more control and sending them a fixed amount of money, relaxing federal mandates and strengthening the private insurance market.

It also calls for bolstering Health Savings Accounts, which allow people to set aside funds for future health care needs. Republicans have long pushed HSAs, but critics say only higher-income Americans can afford to use them.

"The Republican answer needs to address the things Americans are telling us that we want," said Marie Fishpaw, director of domestic policy studies at Heritage, which is part of the coalition. "They want to make sure that they and the people they love don't lose access to coverage or care if they get sick. They want lower costs and they want better choices."