Former Maryland Gov. Martin O’Malley said in a statement Tuesday he will not run for retiring Senator Barbara Mikulski’s seat.

“Senator Mikulski has done an outstanding job representing Maryland in the U.S. Senate for nearly 30 years. I am hopeful and confident that very capable public servants with a desire to serve in the Senate will step up as candidates for this important office. I will not be one of them,” O’Malley said.

On Monday, O’Malley declined to comment on a potential run.

“Today is a day to reflect on Senator Mikulski’s service to the people of Maryland, not engage in political speculation,” O’Malley’s spokesperson, Lis Smith, told BuzzFeed News.

Republicans said Monday that they now view the Maryland open seat as a pickup opportunity in 2016, despite the fact that no Republican has won a Senate race in the state since 1980.

A serious GOP effort in Maryland would require Democrats to spend money in the state they weren’t planning on in 2016.

O’Malley, a two-term Democratic governor with a legacy lauded by progressives, would have been be a strong Democratic candidate in a state with a number of other potential Democratic candidates. But running for Senate would have meant abandoning his uphill bid for his party’s presidential nomination, which as already seen him travel to early primary states and hire staff.