The Senate on Wednesday will continue its efforts to find some version of Obamacare repeal legislation that can get at least 50 votes, a day after Senate Majority Leader Mitch McConnell scored a significant but symbolic victory in opening the debate.

Although Senate Republican leadership was able to scrape together the bare majority to move into debate – an achievement that was in question even as the votes were being cast – it does not expect to be able to find the votes to pass a full repeal during Wednesday's votes.

The best result of Wednesday's "vote-o-rama" would be a series of amendments to compile what has become known as the "skinny repeal," involving the elimination of Obamacare's individual and employer mandates and some of its taxes.

Debate on the legislation, limited to 20 hours because of special budget reconciliation rules that allow bills to pass with a simple majority, began on Tuesday night after the Senate narrowly agreed on the procedural measure with the help of Vice President Mike Pence's tie-breaking vote.

But GOP leadership was dealt a blow shortly after, when Tuesday evening, the preferred plan to repeal and replace Obamacare, known as the Better Care Reconciliation Act, failed 43-57 on a procedural motion with nine Republicans joining all Democrats against it.

It was not anticipated that the leadership's preferred bill, which includes an amendment pushed by Sen. Ted Cruz of Texas, would garner the support of at least 50 senators. But the nine that opposed it, including some who had not previously aired their objections such as Sen. Tom Cotton of Arkansas, Lindsey Graham of South Carolina and Bob Corker of Tennessee, was an unexpected blow.

In what is expected to be a day of marathon voting, lawmakers are expected to first consider a version of a 2015 bill that fully repealed the Affordable Care Act, with a two-year delay to give themselves the opportunity to come up with a replacement.

That bill – which two years ago passed the Senate 52-47 and was eventually vetoed by President Barack Obama – is the preferred choice of some conservatives, who have pressed for more substantial repeal of the existing law, but opposed by moderates who fear setting a repeal clock without a replacement plan ready will destabilize the insurance markets.

It is widely expected to fail to get enough votes to be adopted.

Another amendment that is expected to come up, sponsored by Sen. Rob Portman of Ohio and meant to assuage his and others' concerns that repealing Obamacare would slash Medicaid funding aimed at combating the opioid epidemic, would add $100 million to a stability fund to help low-income patients who lose Medicaid coverage.

But that bill, which hasn't been evaluated by the Congressional Budget Office, is not eligible to be considered under reconciliation rules and thus would need 60 votes. It is unlikely that Democrats will back the amendment, ensuring its failure.

Even the so-called "skinny repeal," which only tackles a few core parts of the existing law, is not a sure bet.

Sen. Susan Collins of Maine, who has emerged as the toughest Republican vote to sway, warned on Tuesday that repealing the individual mandate without replacing it was inadequate.

Collins favors legislation, which she co-authored with Sen. Bill Cassidy, R-La., that would auto-enroll uninsured individuals but would allow them to opt-out if they don't want insurance.