COLUMBIA - The S.C. Senate tentatively passed the first comprehensive ethics reform since the 1990s on Thursday, but senators stripped a provision from the measure that some lawmakers had said was the key to instilling confidence in the Legislature.

Some senators also vowed to continue the debate when the Senate reconvenes on Tuesday, and cautioned that ethics reform is not yet a done deal. The measure must receive one more affirmative vote before moving on to the House, which passed its own ethics reform bill last year and will get a chance at a renewed debate.

Under the measure, passed 37-3, state lawmakers would have to disclose their personal sources of income; so-called Leadership Political Action Committees, which many have said are abused, would be banned; and secretive outside groups that spend money on campaigns would have to divulge their sources of funds.

Sens. Lee Bright, R-Spartanburg, Kevin Bryant, R-Anderson, and Thomas Corbin, R-Greenville, voted against the measure.

Many lawmakers, including Sen. Chip Campsen, R-Charleston, had also included a new independent ethics commission that would be responsible for investigating ethics complaints against Senate and House members. The results of those investigations would then be sent to the full Senate and House ethics committees. That provision, as well as some competing ideas for an independent investigation, were shelved after senators couldn't agree.

"If and when there's another incident . they're all going to be out here saying 'you know what it's another case of those guys investigating themselves,'" said Sen. Larry Martin, R-Pickens.

Others said that the Senate has shown it can police itself. Most recently, former Charleston Sen. Robert Ford, D-Charleston, resigned from the Senate after he faced allegations from the Senate Ethics Committee of using his campaign account for personal expenses, including adult toys.

Lawmakers are watching closely what House Speaker Bobby Harrell, R-Charleston, who is currently being investigated by a grand jury for alleged ethics violations, recommends for ethics reform. The speaker faces allegations of using his campaign account for personal use and questions about whether he properly expensed trips on his personal plane, among other allegations.

Several senators said that ethics reform faces a long road. Even if the Senate passes its bill next week, the House would take up its own debate and then the two sides would have to hash out their differences.

Sen. Vincent Sheheen, D-Camden, said that he plans to prolong the debate next week and offer several amendments. He said he's not sure how "historic" the ethics reform bill is without an independent panel to investigate lawmakers and full income disclosure - which would include the amounts, not just the source of lawmakers' private funds, he said. "I call this an improvement," he said.

The debate is expected to continue on Tuesday.