Democratic U.S. Senate candidate John Walsh has hired several high-profile consultants to work on his campaign, including firms with experience in previous high-stakes Colorado races, his campaign said Thursday.

Walsh, a former U.S. attorney for Colorado, is one of nine Democrats vying for the chance to take on Republican Cory Gardner, considered the most vulnerable Republican senator on the ballot next year.

The consultants signing on with Walsh include a national advertising firm that worked for U.S. Sen. Michael Bennet’s successful 2016 re-election bid and did independent work on both of Gov. John Hickenlooper’s winning gubernatorial runs, a strategist who worked for former U.S. Sen. Mark Udall’s 2014 campaign, and the digital firm that worked for both Bennet and Udall’s most recent runs.

In addition, the Walsh campaign has hired the national polling firm named “Pollster of the Year” for 2019 by a leading trade group.

“With this team of strategists and tacticians on board, we are well-positioned to win next June’s primary, unseat Cory Gardner, and restore a Democratic majority to the Senate,” said Andrew Markoff, Walsh’s campaign manager, in a statement.

“This team has a deep history of competing in top-flight Senate races, statewide races in Colorado, and even a race against Gardner himself.”

The consultants assisting Walsh are:

? Paid media firm GPS Impact, helmed by Andi Johnson, Jay Howser, and Roy Temple, who worked on Bennet’s 2016 race, as well as that of U.S. Sens. Bob Casey of Pennsylvania, Dick Durban of Illinois and Tammy Baldwin of Wisconsin. The firm also produced ads funded by independent expenditure groups for Hickenlooper’s 2010 and 2014 campaigns.

? Strategist and direct mail consultant Mike Muir of Ambrosino, Muir, Hansen & Crounse worked on Udall’s winning 2008 race and the 2014 race he lost to Gardner. His firm worked on the campaigns of U.S. Sens. Jacky Rosen of Nevada and Kirsten Sinema of Arizona, two Democrats who won Republican-held seats in the last cycle.

? Pollsters Molly Murphy and Matt Hogan of ALG Research have worked with the Democratic Senate Campaign Committee, the Democratic Congressional Campaign Committee and the Democratic Governors Association. Murphy was named top pollster this year by the American Association of Political Consultants following her work on Sinema’s campaign, and Hogan has experience working for the Democratic nominee in each of the last four presidential races.

? Digital consultants Zach Knaus and Dillon Doyle of Denver-based 4degre.es worked for Udall in 2014 and set fundraising records last cycle with award-winning campaigns in congressional races across the country.