(Bloomberg) -- Several key Republicanholdouts on health-care legislation said they will vote to begindebate Tuesday afternoon, even though senators don’t know exactlywhere the legislation will end up.

It’s unclear whether they have the 50 votes needed to beginconsidering a version of Majority Leader Mitch McConnell’sreplacement bill or a stripped-down bill that would repeal much ofObamacare with a two-year delay.

“I will vote to move forward and give us a chance to address theunworkable aspects of the law that have left many Nevadans --particularly those living in rural areas -- with dwindling or nochoices,” Republican Senator Dean Heller of Nevada said in astatement. “If the final product isn’t improved for the state ofNevada, then I will not vote for it; if it is improved, I willsupport it.”

Other holdouts, including Rand Paul of Kentucky, said they tooplan to vote to begin debate. Paul said McConnell told him the planis to take up a simple repeal of Obamacare with a two-year delay,as Paul has urged.

"If that is the plan, I will vote to proceed to have this vote,"the senator wrote on Twitter. Paul also said that if the simplerepeal doesn’t pass, "I’ve also been been told we will vote onwhatever version of CLEAN repeal we can pass."

Republican Arizona Senator John McCain, who was diagnosed thismonth with brain cancer, returned to Washington Tuesday for thevote. His presence could provide an emotional lift to GOPlawmakers, whom President Donald Trump urged to seize themoment.

For a Senate leader like McConnell who takes pride inengineering the outcomes he wants, it’s an uncharacteristic gamble.A close vote could put even more pressure on holdouts to back GOPleaders. But a defeat by a wide margin could doom the repealeffort, possibly for good.

McConnell pleaded with his colleagues Tuesday to open thedebate.

“We can do better than Obamacare, and we have a responsibilityto the American people to do that,” he said on the Senate floor.“Today’s vote to begin debate is the first step. We should takeit.”

Senator Roy Blunt of Missouri, a member of the leadership team,said Tuesday he can’t say whether McConnell has the votes to getthe health debate started.

“As you know, Senator McConnell is pretty closely held,” Bluntsaid.

Trump tried to apply maximum pressure on senators ahead of thevote to pass some kind of repeal measure.

‘Obamacare Nightmare’

“Any senator who votes against starting debate is tellingAmerica that you are fine with the Obamacare nightmare,” he said ina televised statement Monday from the White House.

The president, who criticized McCain during the 2016 campaignfor being captured during the Vietnam War, tweeted Tuesday it was“so great” and “brave” that the “American hero” was returning tovote, and told Republicans he has a “pen in hand” to sign anObamacare repeal -- or repeal-and-replace -- measure if they “arewilling to step up to the plate!”

John Cornyn, the No. 2 Senate Republican, said the aim is forRepublicans to pass something and go to conference with theHouse.

“Everything’s on the table. It’s whatever we can get out of theSenate and get to a conference,” he said when asked aboutpossibility of a stripped-down repeal measure that would eliminatethe mandates and the medical device tax.

With Republicans holding a 52-48 margin in the Senate,Republicans can only lose two Republicans and still pass a repealbill. Vice President Mike Pence could cast a tie-breaking vote.

Susan Collins of Maine said she will vote against beginningdebate on any of the measures currently on offer.

QuickTake Q&A: This Unelected Official Holds Sway on HealthCare

Senator John Thune, the No. 3 Senate Republican, said theMcConnell bill is still being tweaked to deal with parliamentaryrulings and potentially to appeal to holdout senators like RobPortman of Ohio.

But Paul said he doesn’t know if any of his amendments have beensent to CBO to see if they qualify under a fast-track mechanismthat would allow the health bill to pass with 50 votes instead of60.

Hard Work

“Leadership is going to have to work a lot harder to give anopportunity for conservatives to want to get on this bill,” hesaid.

Thune said a majority of Republicans want to hold a vote even ifthey don’t have the votes to start debate. “However it turns out,we’re ready to move.”

“I’m still hoping we’re going to get there,” he said.

GOP leaders are making a pitch to senators that they will eachget a chance to vote on their preferred bill and that the finalmeasure will be put together by leadership at the end of thedebate. McConnell said the measures that would get votes includethe 2015 Obamacare-repeal bill with a two-year delay that wasvetoed by President Barack Obama. Trump would sign such a bill, themajority leader said.

But it’s been difficult for McConnell to win over moderateholdouts without alienating conservative Republicans who haveraised objections amid unified Democratic opposition.

Outside groups have also ramped up the pressure, withconservative organizations pressuring Republicans to deliver onseven years of promises to repeal Obamacare.

Seniors’ Lobby

AARP, the powerful lobby group that represents older Americans,urged the Senate to reject the measure and said it wouldcommunicate to members in key states how their senators voted.

“We will report to all 38 million AARP members how theirSenators vote, via ads, our print publications, social media andmore,” the group said Monday night on Twitter.

Pence is expected to be available Tuesday at the Senate in casehis vote is needed to break a tie, Health and Human ServicesSecretary Tom Price told reporters. Trump’s budget office issued astatement urging senators to agree to begin debate.

Several Republicans have already said they oppose repealingObamacare without a replacement, including Collins.

‘Still Fluid’

Senator Pat Roberts of Kansas, a GOP member of the healthcommittee, said senators are discussing revisions to McConnell’splan to replace Obamacare, which collapsed for lack of support lastweek. The majority leader then said he would seek to bring a simplerepeal of Obamacare to the floor early this week, but that proposalalso fell apart amid opposition from Collins and others.

“It’s still fluid,” said Roberts, who added that he wants tosupport whatever plan emerges because he opposes leaving Obamacarein place.

Cornyn said Monday the GOP won’t give up on replacing Obamacareif the Senate can’t pass it this week. “If for some reason wearen’t able to muster the votes tomorrow, which I’m increasinglyoptimistic we will, it’s not the end of it," he said.

Roberts said his main concern is the effect of spending cuts onrural hospitals that get Medicaid funds. “Under the current system,they’re just not going to be able to make it," Roberts said. "We’vejust got to figure out a way to make that work better.”

He said he was in touch over the weekend with Seema Verma, theTrump administration’s head of Medicare and Medicaid, and that herproposal to make up some funding with non-Medicaid money haspotential.

It will be hard to get people who have taken hard stands againstMcConnell’s plan or portions of it to change their positions,Roberts said.

‘Awfully Difficult’

“It’s awfully difficult when people climb the tree and get outon a limb and say, ‘I’m going to vote no,”’ the Kansas senatorsaid. “For them to skinny back down that tree, that’s tough. Andthey have to have some very good reasons as to why that’s thecase.”

Efforts to resurrect McConnell’s Obamacare replacement suffereda further blow on Friday when the Senate parliamentarian issued apreliminary finding that key parts of the proposal don’t qualifyfor the fast-track procedure being used by the GOP. Those partswould require 60 votes rather than the simple majority the GOPseeks to use, Parliamentarian Elizabeth MacDonough said.

Among them are provisions that would defund Planned Parenthoodfor a year, prevent tax credits from being used to buy insurancepolicies that cover abortion, and encourage people to havecontinuous insurance by barring those without coverage for at leasttwo months from buying new insurance for half a year.

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