MADISON, Wis. — Gov. Scott Walker refused to say Thursday why he withdrew his nomination to the University of Wisconsin Board of Regents of a UW-Platteville student who signed a petition to recall him from office.

Walker announced Monday that he was appointing Josh Inglett, 20, to the Board of Regents as one of two student representatives. Then on Wednesday, just hours after Inglett said he told the governor's office he signed the recall petition, the appointment was rescinded.

"I feel like it's a public attack on my character," Inglett told The Associated Press Thursday, referring to the withdrawn appointment.

A pair of state senators, one Republican and one Democrat, urged Walker on Thursday to reconsider and not use signing the recall petition as a litmus test for state service. But Walker wasn't budging, or explaining his reversal.

"We've got plenty of other good candidates and we're not going to get into specifics about it," Walker told reporters after a speech. "I'm not going to comment one way or the other."

Walker said he didn't want to talk about his reasons for the reversal "in the interest of not pulling him through the details on this."

Inglett said he was never asked whether he signed the recall during the four-month vetting process and he didn't see it as an issue.

"I figured if they thought that was important they would have asked," Inglett said. Walker's deputy chief of staff told him in a Thursday morning phone call that the governor was rescinding the appointment because he thought Inglett would have trouble getting confirmed in the Republican-controlled Senate, Inglett said.

Democratic state Sen. Jon Erpenbach called Walker's decision to rescind the appointment "a gutless move."

"This is a college kid versus a guy who's talking about running for president," Erpenbach said at a news conference.

Republican Sen. Dale Schultz, in a letter to Walker, asked the governor to show mercy and help the state heal from the recall election by appointing Inglett.

More than 900,000 people signed the petition in 2011 and 2012 to force a recall election for Walker, a Republican. Walker prevailed in the June 2012 election, becoming the first governor in U.S. history to win a recall.

Online databases are available showing who signed the recall. That public record has caused headaches for some public officials, including judges who signed the recall and state Superintendent Tony Evers, who has worked closely with Walker on a number of education issues.

When asked Thursday if he checks all of his appointees against the list of those who signed the recall, Walker said, "I don't do anything in that regard." He said he's appointed a "broad spectrum" of Republicans and Democrats to a variety of positions on boards, commissions and other posts throughout the state.

Whether Inglett signed the petition or not shouldn't be an issue, Erpenbach said.

"This is absolute McCarthyism. It's the very definition of it," Erpenbach said. "No legislator and no governor should make the litmus test did you sign or didn't you sign. ... The question is whether or not you are qualified to do the job."

Walker praised Inglett, who is majoring in engineering physics and works as a resident assistant, in his news release announcing the appointment Monday.

"The student's perspective is especially vital to the effectiveness of the Board of Regents, and I know he will serve the UW System and his fellow students well," Walker said then.

Republican Assembly Speaker Robin Vos, who served as a student regent from 1989 to 1991, defended Walker and said Inglett should have told Walker he signed the petition without being asked first.

"It's really inherent upon the nominee to be honest and forthcoming about issues that could affect them not being nominated," Vos said.

Along with Inglett, Walker also named former state auditor Jan Mueller and former Republican Lt. Gov. Margaret Farrow to the Board of Regents.

Both Farrow and Mueller were expected to be confirmed by the Senate as early as next week.

The 18-member Board of Regents is responsible for establishing policies and rules for governing the UW System. Fourteen citizen members are appointed by the governor to seven-year terms. The students serve two-year terms and have the same voting privileges as other members. The other two members are the state superintendent of schools and the president or a designee of the Wisconsin Technical College System Board.

Inglett's signing of the recall petition, and Walker's decision to rescind his nomination, was first reported by