The Senate rolled toward passage of a $2.6 billion, campaign-season drug bill Friday that would dangle the possibility of the death penalty in front of many drug offenders who kill.

Senators were debating an amendment that would allow judges to strip convicted drug users of many federal benefits, including student loans, mortgage guarantees and licenses. The benefits could be halted for up to one year for a first conviction and for five years for additional convictions."If you've got a license to operate a radio station and you're smoking marijuana, you're going to be subject to losing that license, and clearly our intent is to say here that we are not going to tolerate the use of marijuana," said the provision's sponsor, Sen. Phil Gramm, R-Texas.

Liberals mounted a fight against the proposal, arguing that it was too harsh. "Why not adopt the Moslem way of doing things?" asked Sen. Dan Evans, R-Wash. "Cut off a hand for a first conviction. Cut off the other one for a second conviction. That would be a deterrent."

Lawmakers who feared earlier that the wide-ranging measure might be stillborn because of a torrent of more than 100 amendments began feeling more optimistic Thursday after a mixture of private bargaining sessions and floor debates eased several potential logjams.

"I believe the end is in sight now," Senate Minority Leader Bob Dole, R-Kan., told his colleagues as they ended their work Thursday evening.

Congress, which had hoped to adjourn Friday, is expected to return next week to try to finish the measure. With 33 Senate seats and all 435 House seats being contested, many incumbents would like to have bragging rights to a tough, crime-fighting package.

Senators still had more than 50 amendments to wade through Friday. They vary from strengthening child pornography laws and encouraging states to confiscate the drivers' licenses of drunken motorists on the spot to requiring warning labels on containers of alcoholic beverages.

The House has already passed its version of the bill, which contains a somewhat broader capital punishment provision. House members and senators would have to work out their differences before sending the bill to President Reagan for his signature.