Former Iowa Lt. Gov. Patty Judge plans to challenge longtime U.S. Sen. Chuck Grassley, R-Iowa, according to a report from The Des Moines Register on Thursday.

Judge, who served under Gov. Chet Culver from 2007 until his defeat in 2011, is expected to announce her candidacy Friday, the Register reported, citing sources in Washington and Des Moines. 

The challenge will come in the midst of the Supreme Court vacancy, which has pushed Grassley, the Senate Judiciary Committee chairman, into the national spotlight over the GOP’s refusal to consider any nominee from President Obama.

“I don’t like this double-speak,” Judge told the Register last week. “I don’t like this deliberate obstruction of the process. I think Chuck Grassley owes us better. He’s been with us a long time. Maybe he’s been with us too long.”

Before her role under Culver, Judge served in the Iowa Senate from 1992 to 1998. She also served as Secretary of Agriculture under Gov. Tom Vilsack from 1999-2007.

Judge would become the fourth Democrat to announce her candidacy. State Sen. Rob Hogg, D-Cedar Rapids, is officially on the ballot, while former state Rep. Bob Krause and former state Sen. Tom Fiegen have announced their intentions to run.