Senate Republicans failed Tuesday evening to overcome an objection from Democrats over updated legislation that would overhaul the U.S. health insurance system.

The amendment, a version of a recent proposal from Republicans to repeal and replace large portions of the 2010 health care law and make sweeping changes to Medicaid, failed 43-57.

The bill included a provision from Sen. Rob Portman of Ohio that would have, among other things, poured an additional $100 billion into a state stability fund. The legislation would still phase out the 2010 health care law’s expansion of the entitlement program and put a stricter growth rate on it starting in 2025.

It also included an amendment from Sen. Ted Cruz of Texas that would have allowed insurers to offer plans that are noncompliant with the current requirements in the health care law, so long as they offer a compliant option.

Both the measures lack an independent analysis from the nonpartisan Congressional Budget Office, a requirement under the fast-track budget process the GOP is using to try to advance their health care overhaul bill with a simple majority support.

Because of that, Democrats were able to raise a point of order against the amendment. Republicans then needed to clear a 60-vote threshold in order to bypass that objection.

The chamber is set to hold the first of a series of votes on the House-passed bill to repeal and replace the health care law at noon on Wednesday.

After 20 hours of debate, the Senate will proceed to the so-called vote-a-rama, a process under which unlimited amendments can theoretically be offered. Lawmakers expect that to happen on Thursday.

Republicans are working behind the scenes to try to come to consensus on a “skinny” repeal bill that would only gut smaller portions of the 2010 law. Should such a measure pass, the House and Senate could try to reach a compromise on a broader bill to repeal and replace provisions in the law.