WASHINGTON - Republican leaders in the U.S. Senate on Thursday unveiled their plan to overhaul President Obama's 2010 health care law. Within hours, Texas' two Republican senators took opposite positions on the measure.

While U.S. Sen. John Cornyn took to the floor early Thursday to defend the bill against Democratic criticism, U.S. Sen. Ted Cruz joined a bloc of conservative senators who announced in the afternoon that they couldn't back the bill at this time.

“Currently, for a variety of reasons, we are not ready to vote for this bill, but we are open to negotiation and obtaining more information before it is brought to the floor," Cruz said in a joint statement with U.S. Sens. Rand Paul of Kentucky, Mike Lee of Utah, and Ron Johnson of Wisconsin.

"There are provisions in this draft that represent an improvement to our current healthcare system but it does not appear this draft as written will accomplish the most important promise that we made to Americans: to repeal Obamacare and lower their healthcare costs," they added.

But Cornyn, a member of Senate leadership, fought hard for the bill on the Senate floor Thursday morning.

There are 52 Republicans in the U.S. Senate. Republicans need at least 50 of them to support the bill to pass it, assuming Vice President Mike Pence casts the tie-breaking vote in their favor.

On the Senate floor Thursday, Cornyn single-handedly defended the bill at length against several disgruntled Democrats, including Minority Leader Chuck Schumer from New York, who criticized the way the Republicans crafted the bill.

At one point, Schumer asked Cornyn if Republicans would agree to start over and craft a bipartisan bill.

"If I thought that was a sincere offer, I would take it in a minute, a New York minute,” Cornyn said. "It's been made clear to us that you don't want to participate in the process."

Cornyn called the Affordable Care Act a "failed experiment" that necessitates quick action from the Senate.

Read the full article on the Texas Tribune's website here.