U.S. Rep. John Shadegg, R-Ariz., announced Thursday that he will postpone retirement plans and seek an eighth term in Congress.

Shadegg, 58, had announced last week that he would leave the House despite raising more than $1 million for another run. The decision surprised many Republicans, and 146 of his House colleagues signed a letter pleading for him to return. Leaders of 33 conservative organizations also asked for him to stay.

Shadegg's staff says the congressman spent the week in Arizona with his family mulling over the request to stay.

His decision put on hold career plans for Republican state Senator Jim Waring, who had hoped to run for Shadegg's seat in the 3rd Congressional District. Waring said he won't run against Shadegg.

Shadegg is expected to run against Republican Steve May, who already announced his candidacy.

"The Republican Party has to change," May said. "In 1994, I was a believer, like everyone else was, like John Shadegg was, that we could actually make a difference. Once we took charge, we spent like Democrats, and we behaved like jackasses. And there was no difference."

The Democrats also plan to make a strong bid for the seat. Democratic attorney Bob Lord has raised more than $612,000 to run in the 3rd District.

If he had retired, Shadegg would have added to a growing list of House Republicans heading for the door. During the past 13 months, 28 House Republicans have said they would either leave office or not seek re-election.