U.S. Rep. John Shadegg said Thursday he will reconsider his decision to retire at the end of his term.

Opinion: It could be a short retirement for John Shadegg

He began wavering after learning that more than half of the Republicans in the House have signed a letter asking him to stay. Shadegg, 58, unexpectedly announced his retirement Monday.

The letter is the first of kind and scope in recent memory. One of its three authors, Rep. Mike Pence of Indiana, said he and the others collected 135 signatures in about two hours Thursday afternoon. Pence expected to obtain additional signatures today.

Shadegg said he was aware the letter was being circulated, but had not seen it by Thursday evening.

“I think I have an obligation to take a look at it and consider it,” he told the Tribune. “If it’s 138 members, if it really is 138 members, then I’ve got a duty to at least look at it and give their request fair consideration.”

Shadegg will have to give thought to the arguments presented in the letter and consult with his wife before coming to a decision about his future. He said, “I just need to go through the process.”

Days earlier, Shadegg said he had come to the conclusion that he could be a more forceful voice in the conservative movement in the private sector rather, than as member of the minority party in the House.

Pence and Reps. Jeb Hensarling of Texas and Peter Hoekstra of Michigan wrote and circulated the four-paragraph letter. “Frankly, we were overwhelmed at the response, but not surprised at the esteem at which John Shadegg is held,” Pence said.

The letter to Shadegg states, “As chairman of the Republican Study Committee, a member of House leadership, and a leader in the conservative movement, you are helping Republicans return to core principles. Your intellectual consistency in defense of the Constitution and passionate articulation of conservative principles is in need now more than ever.”

Former Rep. Matt Salmon of Arizona said the show of support is unprecedented.

“I have never seen it in all my years in politics -- never. I’ve seen three or four people come up to somebody and say, ‘You should really run again,’ Salmon said. “I’ve never seen 138 people sign a letter telling somebody to run again.”

Republicans have had plenty of opportunities to write similar letters. Shadegg became the 29th House Republican in the past 13 months to either leave or decline to seek re-election at the end of this term.

“They didn’t do it for the others. I guarantee you that,” said Salmon, who served in the House from 1995 to 2001.

Shadegg’s announcement Monday triggered a surge of Republicans offering themselves as possible candidates to succeed him.

Meanwhile, Democratic challenger Bob Lord became his party’s establishment candidate Thursday with endorsements from Gov. Janet Napolitano, former party chairman Jim Pederson and several others.

Independent Annie Loyd also is seeking the seat for Arizona’s 5th Congressional District, which takes in central and northern Phoenix, Paradise Valley, Carefree and Cave Creek.