After mulling it over for a week, U.S. Rep. Michael N. Castle (R-Del.) has decided to not wage a write-in campaign for the U.S. Senate seat up for grabs on Nov. 2.

After mulling it over for a week, U.S. Rep. Michael N. Castle (R-Del.) has decided to not wage a write-in campaign for the U.S. Senate seat up for grabs on Nov. 2.

Castle made his decision late Wednesday, Sept. 29. More than two weeks ago, Castle, known suffered the first political defeat of his career in a Republican primary against conservative candidate Christine O’Donnell.

O’Donnell was backed by the Tea Party Express, whose moniker stands for Taxed Enough Already, and local Tea Party groups.

Despite his defeat, several Delawareans encouraged Castle to pursue the Senate seat as a write-in candidate for the general election scheduled for Nov. 2, he said in a prepared statement. He listened to those viewpoints and carefully considered staying in the race.

“Jane and I have been humbled by the strong encouragement from so many friends, colleagues and supporters to undertake this effort,” Castle said. “While I would have been honored to represent Delaware in the U.S. Senate, I do not believe that seeking office in this manner is in the best interest of all Delawareans. Therefore, it's time for Jane and me to begin thinking about the next chapter of our lives.”

The congressman is supporting the GOP ticket in DE but will not be endorsing anyone in the U.S. Senate race, spokeswoman Kate Dickens said.

Castle has said that O’Donnell’s campaign went to far in taking things to a personal level in a campaign rife with muckraking from both sides.

O’Donnell released a statement, but would comment on Castle’s decision to not endorse her personally.

“Congressman Castle has served Delaware with distinction and honor and we appreciate his dedication and service to our great state," she said.

O’Donnell faces a tough fight against Democrat Chris Coons, who is in the middle of his second term as New Castle County executive. Coons leads O’Donnell by 11 percentage points, according to a Sept. 15 Rasmussen poll conducted the day after the primary. In a poll of 500 likely voters, 53 percent chose Coons while 42 percent went with O'Donnell. The poll had a margin of error of 4.5 percent.

A write-in campaign by Castle would have hurt Coons more than O’Donnell in the Delaware campaign for U.S. Senate, according to a Rasmussen Reports telephone survey of Delaware voters released Monday, Sept. 27. That poll found Coons would obtain 49 percent support, O’Donnell would earn 40 percent and Castle would pick up 5 percent. (Another 5 percent were undecided.)

But, in the end, Castle chose retirement.

Castle has been the state’s lone U.S. representative since 1993, the longest tenure for any congressman in the Diamond State. He was governor of the state of Delaware from 1985 to 1992 and served as lieutenant governor from 1981 to 1985. Prior to serving in the executive branch, Castle served in the Delaware General Assembly, as state representative from 1966 to 1967 and as a state senator from 1968 to 1976.

“Much of my life has been dedicated to representing Delawareans and it has been my privilege and great honor to serve you and represent our state in the legislature, as Lt. Governor, Governor and in the United States House of Representatives,” Castle said in his statement.”

“Delaware is a close community of people who find practical solutions to the complex challenges we face,” he added. “That characteristic is something that makes our State a very special place to live.”