If Johanns decides to run for the seat and Nebraska elects him, Bush said, “he would make an outstanding member of the United States Senate. There is no doubt in my mind.”

Johanns also used the announcement to highlight his ties not to Washington, but to Nebraska, a place where he said “the richness of the land is only equaled by the character of its people.”

“In a sense, I brought Nebraskans with me to every Cabinet meeting, every hearing on Capitol Hill, every negotiating session in faraway countries,” said Johanns, who was also mayor of Lincoln.

Johanns would face competition in a GOP primary from state Attorney General Jon Bruning and former Rep. Hal Daub, who announced his candidacy earlier this week. If he wins the primary, Johanns could face off in a race guaranteed to get national attention with former Sen. Bob Kerrey (D-Neb.), who is considering a run.

Previewing potential campaign arguments, Johanns came under criticism from some farm-state lawmakers on Wednesday when news of his imminent resignation floated. Sen. Kent Conrad (D-N.D.) said Johanns should stay with the Department of Agriculture (USDA) until work on the farm bill is completed.

Some lobbyists, however, said privately that Johanns’ absence would make little difference in the outcome of the farm bill.

Bush said Deputy U.S. Agriculture Secretary Chuck Conner would become acting secretary of agriculture. In a resignation letter to Bush released to reporters, Johanns said this would leave USDA in capable hands.