The last Democrat to represent Colorado’s 4th Congressional District, former U.S. Rep. Betsy Markey, on Monday threw her support behind veterinarian Karen McCormick, one of four Democrats hoping to challenge Republican Ken Buck in next year’s election.

In a statement, Markey said she’s convinced McCormick will work toward “building a stronger middle class, higher household incomes, affordable higher education and job training programs and a future that includes a safe and secure retirement,” adding that she’s proud to endorse the Longmont resident.

McCormick said she was honored to have Markey’s support.

“Both Betsy and I owned and operated successful businesses and like her, I believe in an economy where hard work is rewarded, where everyone pays their fair share and that all Coloradans -not just those at the top -should have an opportunity to get ahead,” the candidate said in a statement.

Markey served one term in Congress almost a decade ago, ousting Republican incumbent Marilyn Musgrave in the 2008 election and then losing a run for a second term to then-state Rep. Cory Cory Gardner, who went on to win a seat in the U.S. Senate in 2014. Markey was the Democratic nominee for state treasurer that same year but lost her bid to unseat Republican Walker Stapleton.

Buck is running for his third term representing the sprawling 4th District, which covers most of the eastern half of the state, anchored by Weld County to the north and most of Douglas County, south of the metro area. He’s facing a primary challenge from former Lone Tree Mayor Jim Gunning.

The other three Democrats running for the heavily Republican seat are Chase Kohne, Larry Germanson and Richard Weil.