JEFFERSON CITY – Missouri Gov. Jay Nixon's choice to run the Department of Economic Development resigned Thursday after the state Senate refused to approve his nomination.

Republican senators argued that Jason Hall, 36, does not have the experience required for the job. Senate President Pro Tem Rob Mayer, a Republican from Dexter, also pointed to an audit critical of the Missouri Technology Corp. during Hall’s tenure as the organization’s executive director. The audit alleged that Hall made political threats against former Auditor Susan Montee and her staff.

“Now is not the time to put someone in that position that lacks experience in the private sector,” Mayer said Thursday morning, later adding: “And his interaction with the former auditor raised some concerns about his maturity.”

Hall had been serving as economic development director since he was appointed to the job Dec. 30. His nomination had garnered support from numerous business groups, including the Missouri Chamber of Commerce and Industry and the Greater Kansas City Chamber of Commerce.

On Wednesday, the Senate Gubernatorial Appointment Committee refused to take a vote on Hall. The Missouri Constitution gives nominees 30 days to be accepted by the senate, and if they are not they are permanently barred from ever holding the position they were nominated for.

The 30-day deadline is tomorrow.

The governor had the option of withdrawing Hall from consideration before the deadline, which would allow him to be reconsidered at a later date. But doing so requires approval from the senate.

Instead of withdrawing his nomination, Hall resigned. The governor's staff pointed to an attorney general opinion that found a nominee appointed while the senate is recessed can resign and still be eligible to be reappointed in the future.

Nixon said Hall will continue as a senior member of his administration. Chris Pieper, deputy council to the governor, will serve as acting director while a search for a permanent director is conducted.

Sen. Joe Keaveny, a St. Louis Democrat, said he was disappointed in how Hall’s nomination was handled.

“I think it’s unfair that we don’t allow the governor to pick his own cabinet,” Keaveny said.

Other senators, including some Democrats, criticized what they believe is a lack of communication from the governor. When Mayer said he had spoken with Nixon about the nomination, Democratic Sen. Ryan McKenna of Crystal City said the rest of the senate is jealous, “because we never get to talk with the governor.”