CNN will hold a town hall Monday night featuring Republican Sens. Lindsey Graham of South Carolina and Bill Cassidy of Louisiana, backers of a last-ditch overhaul of Obamacare, debating Sen. Bernie Sanders, I-Vt. and Amy Klobuchar, D-Minn.

The town hall comes a few days before the Senate is expected to vote on Graham and Cassidy's bill to cut Obamacare's funding and distribute it to states through block grants.

Sanders a few weeks ago reintroduced his own bill that would create a government-run, socialized healthcare system that drew 16 Democratic co-sponsors, several of whom are 2020 presidential hopefuls. Republicans say Sanders' legislation helped them sell a competing vision to senators wary of taking another tough vote on healthcare.

Klobuchar, who comes from a swing state, did not endorse Sanders' bill. She is up for re-election in 2018.

Graham and Cassidy are expected to testify before the Senate Finance Committee Monday on the legislation, which has no had a full analysis from the Congressional Budget Office.

The two senators are pushing to muster 50 votes for the measure, with Vice President Mike Pence serving as the tie-breaking vote. Republicans have until midnight on Sept. 30 to pass the bill or lose the ability to get it through the chamber with only 51 votes as the rules for using the reconciliation tool expire.