The Senate has rejected an effort by young conservative Senators to block a bill to avert a government shutdown on Tuesday.

Friday’s 79-19 vote marks an emphatic defeat for Republican Sens. Ted Cruz of Texas and Mike Lee of Utah. Their effort has sparked opposition from Democrats and from many GOP lawmakers, who worry the tactic could prompt a federal shutdown for which Republicans would be blamed.

Cruz and Lee are backed by outside conservative groups and have been trying to block a House-approved budget bill.

That’s because the bill would deny money for President Barack Obama’s health care law. They oppose the health care law and say blocking the budget bill will force Democrats to negotiate.

This sets up a weekend showdown between Republican House Speaker John Boehner and tea party conservatives in his GOP caucus, which demands that any spending measure must eliminate all money for Obamacare.