It is often said that the Senate is a gentlemen's club where relationships matter, and though that notion seems somewhat quaint in these times of fierce partisan rhetoric and deep ideological divides, the statement could not be truer where Sens. John McCain, R-Ariz., and Joe Lieberman, I-Conn., are concerned.

"He's one of my dearest friends, and I will miss him every day," McCain said of his colleague who is poised to announce in his hometown of Stamford on Wednesday that he will end his Senate career in 2012 after a quarter century of service.

The two men first met in 1989 when Lieberman, then a Democrat, first entered the Senate, having toppled GOP maverick Sen. Lowell Weicker. The 46-year old freshman asked to see McCain, just two years into his own Senate career. "He asked to see me and came by to see me. He said he wanted to work with Republicans. Not everything was sweetness and light (back then), as we like to think today," McCain recalled of their first encounter, and a friendship was born.

Every year thereafter, when possible, the two have led a congressional delegation to Munich for an annual security conference, and McCain said in a phone interview that the two will do so again in a couple of weeks. The bond between the two men has deepened on their long journeys. They would team up on a number of national security issues, over the years, including support for the controversial surge of troops during the Iraq war and on the right way to prosecute prisoners in the war on terror.

It would be that steadfast support for the war that, in 2006, nearly ended Lieberman's career when an upstart Democratic primary opponent forced the senator to change his party I.D. to "Independent" in order to gain re-election.

McCain and Lieberman have joined forces on non-security matters, as well, including a bid to avert a Constitutional crisis over judicial nominations in 2005. McCain and Lieberman, a leader of the moderate wing of the Democratic party, helped to bring together 14 senators in a bipartisan effort to get more of President Bush's nominees through the Democratically-controlled Senate and to leave those nominees at the curb who had what the group called "extraordinary circumstances" against them.

Lieberman's estrangement from his party hit its zenith when he announced his support for McCain's 2008 presidential bid against then-Sen. Barack Obama, D-Ill. At the GOP nominating convention, Lieberman famously said to great applause, "Senator Barack Obama is a gifted and eloquent young man who I think can do great things for our country in the years ahead, but, my friends, eloquence is no substitute for a record, not in these tough times for America."

McCain's fondest memory of his friend of more than 20 years came in late 2007 when Lieberman announced that endorsement in New Hampshire. The Independent senator told Fox News at the time, "There are some things more important than the political parties. One is friendship and the other is I think this guy is the best of all the candidates to unite our country and cross political lines so we can begin to finally solve some of the political problems that we have in this country and to lead us against the war versus Islamic elitist terrorism."

On Wednesday, McCain recalled, with emotion in his voice, "It was a magical moment. I believe his endorsement was key in our winning independents."

Shortly thereafter, the speculation was rampant that McCain would break with tradition and pick Lieberman as his running mate. Asked if the Republican maverick had any regrets that he went another direction, McCain, in his trademark decisive style, said, "No. You make decisions. It's not helpful to look back." But Lieberman reportedly was stunned at the choice, a sentiment he voiced long after the campaign was over.

McCain said Lieberman talked to him months ago about possibly leaving. The two recently "had a long conversation. There's no doubt he had a tough fight ahead of him, but he's had tough fights before. I just think after 40 years, he's ready to do something else. Frankly, I'll miss him not only because of our deep and abiding friendship, but also because there are very few individuals with the knowledge to articulate the way Joe can."

And what will happen to the "Three Musketeers" - which is what McCain and Lieberman like to call their friendship with Sen. Lindsey Graham, R-SC, who became a fast pal when he entered the Senate in 2002? "We'll try and take him with us as consultant," McCain quipped of Lieberman.