This post originally appeared on Huffington Post.

With the Senate planning to take up a bill next month that would raise the minimum wage, Sen. Sherrod Brown (D-Ohio) said Wednesday that he and most of his fellow Democrats would be unwilling to strip out a raise to the “tipped” minimum wage, as the restaurant industry is asking for them to do.

“We’re not going to do this without a significant increase to the tipped minimum wage,” Brown said on a call with reporters, emphasizing that he wouldn’t vote for minimum wage legislation without the increase.

Under federal and state laws, restaurant owners can pay servers and other tipped employees less than the standard minimum wage — and as little as $2.13 per hour — leaving diners to make up the difference through gratuities. Under heavy lobbying from the restaurant industry, the federal tipped minimum wage hasn’t been raised from $2.13 in more than 20 years.

The bill sponsored by Sen. Tom Harkin (D-Iowa) and Rep. George Miller (D-Calif.) would raise the standard minimum wage to $10.10 per hour and peg it to inflation, while setting the tipped minimum wage at 70 percent of that rate, in perpetuity. The tipped minimum wage is currently just 29 percent of the standard minimum.

The restaurant lobby, however, has opposed the Democratic legislation, leading to concerns that restaurant workers could once again be carved out of a minimum wage hike, if such a raise even comes to pass.

The National Restaurant Association has warned that raising the tipped minimum wage would cost restaurant jobs. The D.C.-based lobby and its state affiliates have successfully fought off such raises in the past, including in 1996 with the help of former GOP presidential hopeful Herman Cain. That year, the tipped minimum wage was split off from the standard minimum wage during a Democratic-led increase under President Bill Clinton.

The tipped rate hasn’t budged since, unbeknown to many diners and even members of Congress, Brown noted.

“This NRA is about as powerful as the other NRA,” he said, alluding to the National Rifle Association, “and we’re not gonna cave to them on this.”

The Republican-controlled House hasn’t shown any desire to move the Miller bill, although Democrats like Brown are hoping the minimum wage will become a campaign issue in this year’s mid-term elections.

“The good news here is that — and I can’t speak of course for all of my colleagues — but I’m convinced the great majority of my Democratic colleagues are pretty incensed that this hasn’t been increased in 20 years,” he said. “I have spoken maybe five or six times to the caucus about the tipped minimum wage, and people are very aware of it, when they weren’t in the past.”

Brown said he plans to put forth a resolution in the Senate declaring this Thursday — Feb. 13 — “2.13 Day,” as a reminder of the stagnant tipped minimum wage.

Saru Jayaraman, co-director of the workers’ group Restaurant Opportunities Center United, joined Brown on the call Wednesday, saying that the low tipped minimum wage has left diners to subsidize an increasing share of servers’ salaries.

“This industry over the last 20 years has demanded repeatedly that customers pay their workers’ wages rather than they themselves,” Jayaraman said. “We really at this point demand that the system change. No worker should be dependent on living off the mercy of customers.”