Senate Majority Leader Harry M. Reid (D-Nev.) (Andrew Harrer/Bloomberg)

Senate Majority Leader Harry M. Reid (D-Nev.) intensified his calls for the Washington Redskins to change their name Thursday, saying Native American tribes in his state are insulted by being used as mascots.

Reid's comments came in response to a letter co-signed by 50 Senate Democrats that calls on NFL Commissioner Roger Goodell to change the team's name.

"Sure not going to do any harm," Reid said when asked about the letter. "The NFL has a lot of problems with all the lawsuits being filed against them for their negligence, and it would seem to me that it would make a lot of sense that they should get rid of having a group of Americans as mascots. They're not mascots – they're human beings. I have 22 tribes in Nevada and they're insulted by this cavalier attitude about what they're being called."

Reid said he didn't know why the signatures of Senate Republicans don't appear on the letter. "They should get their own letter," he said.

Sen. Maria Cantwell (D-Wash.), who is the primary author of the letter, told The Washington Post's Dan Steinberg on Thursday that the letter was exclusively distributed to and signed by Democrats, but that she's asked senators of both parties to weigh in on the issue.

“We had to create momentum,” she said in a subsequent telephone interview Thursday. “This was the easiest way to create the momentum. Now we can hopefully get our colleagues to think more seriously about this, and to sign on, too. It’s just a proud moment, to get 50 people in the United States Senate to sign on. I don't think we would have been able to do that a few years ago.”