U.S. Rep. Keith Ellison of Minneapolis endorsed Vermont Sen. Bernie Sanders for president Monday, backing a liberal underdog over the Democratic front-runner Hillary Rodham Clinton.

"For decades, Bernie has demonstrated a willingness to push for progressive ideas that will help American families and restore balance to our economy, which has favored the millionaires and billionaires for way too long," Ellison said in a prepared statement.

Ellison is only the second Democrat in Congress to publicly back Sanders over Clinton. He is also the first prominent Minnesota Democrat to get behind Sanders, while dozens have thrown in with the former first lady and U.S. secretary of state.

Clinton has continued to lead Sanders in most polls of the Democratic contest, but he has shown surprising strength in recent months — particularly in his ability to draw large, enthusiastic crowds to campaign events. A Sanders rally in Minneapolis in June drew more than 3,000 people.

"Bernie has shown that he has the ability to create a renaissance in civic participation by exciting those who are least likely to vote," Ellison said.

Ellison first revealed his presidential pick on MSNBC. A spokesman for the congressman said he did not have time Monday for an interview with the Star Tribune. His congressional district includes Minneapolis and several nearby suburbs.

Ellison and Rep. Raul ­Grijalva of Texas are the only two members of Congress to endorse Sanders so far. They are co-chairs of the Congressional Progressive Caucus; a group that Sanders helped establish when he was in the House. He is now its only member from the U.S. Senate.

Past connections

Sanders is a political independent, but he caucuses with Senate Democrats and is seeking the Democratic presidential nomination. Mike Casca, a former press aide to Ellison, is the press secretary for Sanders' presidential campaign.

Ellison and Sanders have co-sponsored a number of unsuccessful policy proposals, including a minimum-wage increase, a ban on privately run prisons and the cessation of government subsidies to big oil companies.

"He is committed to investing in our education system and infrastructure, raising the minimum wage, addressing climate change, fixing our criminal justice system, reforming our financial markets, and pushing for peace and diplomacy abroad," ­Ellison said.

While Ellison is the first DFLer of note to back Sanders, the list of Minnesota supporters for Clinton is long. It includes U.S. Sens. Amy Klobuchar and Al Franken, Gov. Mark Dayton and Lt. Gov. Tina Smith, U.S. Rep. Tim Walz of Mankato, Minneapolis Mayor Betsy Hodges and St. Paul Mayor Chris Coleman, more than a dozen state legislators, and numerous additional party activists and interest group leaders.

"Keith Ellison is one of the great progressive leaders in the country leading the fight for the rights of working families and the environment," Sanders said in a statement furnished by his campaign. "I look forward to working with him to create a government which represents all Americans and not just the billionaires."

On Tuesday night, Clinton and Sanders along with three other Democratic candidates for president — former Maryland Gov. Martin O'Malley, former Virginia U.S. Sen. James Webb and former Rhode Island U.S. Sen. and Gov. Lincoln Chafee — will join in the first Democratic debate in Las Vegas.