(Laurence Kesterson / Reuters)

Hours after 50 U.S. Senators called on the NFL to formally endorse a Washington Redskins name change, Sen. Maria Cantwell (D-Wash.) vowed to continue pushing this issue with an ever-broader coalition of support.

In a speech on the Senate floor Thursday afternoon, Cantwell requested that other colleagues contact the league office about Washington’s team name, either by signing the existing letter endorsed by 49 Senators, or by writing one of their own, as did Bill Nelson (D-Fla.).

“I’m convinced that if each member of this body speaks on this issue, and is forceful in their resolve, that we can help initiate change,” Cantwell said on the Senate floor.

While this week’s letter was exclusively distributed to and signed by Democrats, Cantwell asked Senators from both sides of the aisle 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.”

Earlier Thursday, NFL spokesman Brian McCarthy responded to the letter, saying in a statement that the NFL “has long demonstrated a commitment to progressive leadership on issues of diversity and inclusion, both on and off the field. The intent of the team’s name has always been to present a strong, positive and respectful image. The name is not used by the team or the NFL in any other context, though we respect those that view it differently.”

Cantwell, while expressing admiration for the NBA’s handling of Clippers owner Donald’s Sterling’s controversial comments, rejected the NFL’s statement.

“They obviously are continuing to disrespect Native Americans, and everybody from the UN to the D.C. City Council thinks so,” she said. “So they can continue to hold a very, very narrow view of the world. But as more and more people sign on to help us, they’re going to be on the wrong side of history.”

Cantwell traced her increased involvement in the issue to the 2013 playoff game between the Redskins and Seahawks at FedEx Field. Attending the game to support the visiting Seahawks, she said the presentation of Washington’s team was “just so shocking to me,” and that the Redskins were offering “a caricature of a team that is not just respected by Indian Country.”

Several months ago, Cantwell showed her caucus members a video opposing the name, made by the National Congress of American Indians before the Super Bowl, and then initiated the process of rallying support for a letter. Cantwell said she has already had “lots of conversations” with Republican senators on the issue, and insisted that Congress’s involvement need not be merely symbolic.

“We wish we were where the NBA was in dealing with its ownership,” she said. “We’re not, but we’re definitely showing the NFL that we’re watching. We have talked about their tax status; I’m sure that will be discussed in the future. But this is about getting people to continue the fight. We hope a lot of people will join us; we hope more people will watch the video and really understand.”

In her speech on the Senate floor Thursday, Cantwell freely acknowledged that “this may not even be the top issue in Indian Country,” listing other problems like understaffed hospitals, challenging schools, decaying infrastructure and issues with fishing rights.

“There are many, many issues in what we refer to as Indian Country that I would say are about the health and safety and welfare of those individuals,” she said. “Yet this issue is a reminder to all of us that intolerance in our communities is a problem. We’re here to say that we respect these tribal entities that have requested this name change. … So I hope my colleagues will help us in this effort to get the NFL to do the right thing.”