Senate Republicans on Sunday unveiled the latest version of an Obamacare overhaul bill as they face a five-day window for passage and dwindling support within their own party.

Three GOP senators came out against the former version of the bill, including Rand Paul of Kentucky, John McCain of Arizona and Ted Cruz of Texas. Sen. Susan Collins, R-Maine, has not explicitly said she would vote against the bill, instead conveying she is leaning against it and it would be difficult for her to envision a scenario in which it would earn her support.