Correction Appended

Sen. John Ensign on Monday capped off a 15-year Congressional career with a speech to a nearly empty Senate chamber, striking notes alternately apologetic and defensive.

The Nevadan and former Republican leader, who has resigned effective today, asked for forgiveness from his Senate colleagues, none of whom joined him on the floor to publicly offer it.

But in the same breath, Ensign sought to justify how he came to leave the Senate under a cloud, having fallen from his position as one of his party’s most promising lights to being a scandal-tarred liability.

Ensign’s departure was seen as necessary: He resigned because he faced an ongoing Senate ethics investigation into his affair with the wife of a top aide and a party anxious to field a candidate with less baggage.

Ensign’s speech reflected the mixed emotions of a man leaving a job he wasn’t yet ready to surrender.

The Republican began his remarks by touting his own legislative record, citing his feats in passing public-lands bills and health care reforms. In fact, Ensign said, his accomplishments during his tenure in the House and Senate were simply too many to list.

“I could speak at length about my fight for lower taxes and individual freedoms, protection of constitutional rights, the dignity of our servicemen and women, education reform, and so much more, but there is not enough time,” he said.

After proudly rattling off the highlights of his record, Ensign went on to confess that his years in the Senate had made him arrogant, despite his best efforts.

“I even tried not to become caught up in my own self-importance. Unfortunately, the urge to believe in it was stronger than the power to fight it,” he said.

But even his growing ego, he said, was not a burden he bore alone. Ensign said he did not surround himself with staffers who were willing to check his behavior.

“This is how dangerous the feeling of power and adulation can be,” he said. “My caution to all of my colleagues is to surround yourself with people who will be honest with you about how you really are and what you are becoming.”

Despite its mixed messages, Ensign’s speech elicited sympathy from his soon-to-be-former colleagues.

Senate Majority Leader Harry Reid (D) said he valued his fellow Nevadan’s “partnership” throughout the years they served together.

“As John enters the next chapter in his life and departs from the United State Senate, I wish him and his family well as they work through this difficult time,” Reid said in a statement. The leader strayed from tradition and did not honor his home-state colleague on the floor.

In his speech, Ensign, too, thanked Reid. Among his confessions was the revelation that he and Reid, though on opposite sides of the political spectrum, had developed a warm personal friendship. That’s one reason they refused to campaign against one another in what have been close elections.

Had Ensign stayed in office, he would almost certainly have faced a primary challenge from Republican Rep. Dean Heller in 2012. Heller last week was appointed by Nevada Gov. Brian Sandoval (R) to succeed Ensign.

Some who listened to the address expressed sorrow at watching Ensign’s public downfall.

“This is the correct conclusion to a sad situation,” one Senate Republican aide said. “His farewell speech was gracious and appropriate.”

Others, though, weren’t so charitable.

“Good riddance,” another Senate Republican aide said.

Ensign was once seen as a rising star in GOP circles. He served as chairman of the National Republican Senatorial Committee during the 2008 cycle and after that was the chairman of the Senate Republican Policy Committee, the No. 4 position among the chamber’s GOP Members.

He was mentioned as a possible 2012 presidential candidate and even made a trip to Iowa in 2009. But his prospects were dashed when, later that year, his top aide, Doug Hampton, revealed that Ensign had an affair with his wife. But the revelation that Ensign’s parents had paid the couple $96,000 was the nail in the Senator’s political coffin, especially since Hampton was about to go public.

“It’s a very sad end to a career that just a few political moments ago seemed to be heading toward something big,” a senior GOP aide said.

And as Ensign prepared to join the roster of scandal-tarnished former Senators, the Nevada Republican also associated himself with two members of that club. He confessed that he regretted calling for the resignations of ex-Sen. Larry Craig (Idaho) and the late Sen. Ted Stevens (Alaska). He singled out those Republicans after Craig’s arrest in an airport men’s restroom sex sting and when Stevens was facing federal charges of corruption.

Stevens was found not guilty, and he died in a plane crash last year.

Ensign said that after his own scandal broke, he asked both men for forgiveness. Craig, in fact, was one of the first to call him after the news broke, he said.

“Each of these men were gracious enough to forgive me, even though publicly, I did not show them the same grace.”

Throughout the speech, the Senate floor remained empty, with only a handful of aides perched on the staff bench. No Senator came to the floor, as is custom for a Senator’s farewell address.

Ensign closed by addressing his absent colleagues.

“I bid you farewell,” he said. “Know that you will be in my prayers. I yield the floor and note the absence of a quorum.”

With that, he strode into the empty Cloakroom in the rear of the chamber.

Correction: May 2, 2011

The article mischaracterized Cynthia Hampton’s role in the affair.