West Virginia's 5-term Democratic Senator Jay Rockefeller has announced he will retire when his term expires in 2014.

Politico:

In an interview with POLITICO, Rockefeller - the chairman of the Commerce, Science and Transportation Committee and one of the most senior Senate Democrats - said he had been wrestling with the question of whether to run again since October but had not made up his mind to retire until very recently.

"I'm going to serve out my term," the 75-year-old Rockefeller said. "It was a very hard decision for me. Once it's made, like any hard decision, it eases up. But it was a very tough decision for me."

Rockefeller is scheduled to make a formal announcement at 11 a.m. back home in West Virginia.

Rockefeller said he decided to go public with his retirement now - one that is sure to shake up the 2014 Senate landscape - because it felt like the right move and because he didn't want months of public speculation over his political future.

"It's part of my nature," Rockefeller said. "One is, I think that always in me, I want to do things - if I have a statement to make or an announcement that has at least some consequence to it - I want to do it in the way that I want to do it, at the time that I want to do it, with the words that I want to use.

"I do it now because I'd just rather clear the air and just get on with things," he added.

Rockefeller acknowledged that Democrats will have a hard time holding onto his West Virginia Senate seat, but he insisted that he wasn't leaving because of fear of any GOP challenger or fear that he wouldn't win next year.

"Political opposition, I never worried about that," Rockefeller insisted. "It's not a part of this. It was easy enough not to have to worry about that."

There is no shortage of possible GOP candidates - any of which would probably be favored over the Democratic choice. AT's political correspondent Rich Baehr believes that 6-term Rep. Shelly Capito would be the favorite. She announced in November that she would seek the seat and has a head start on other candidates.

This is very good news overall for the GOP Senate prospects. Josh Krashaar of National Journal laid out the map a few weeks ago:

After losing two seats, newly-minted NRSC chairman Jerry Moran now needs to net six seats to win back control of the Senate.  The formula is simple, but challenging: Win six of the 7 Democratic-held seats in states Romney carried (Alaska, Arkansas, Louisiana, Montana, North Carolina, South Dakota, West Virginia), or expand their wiggle room by ousting a vulnerable Democrat like Minnesota Sen. Al Franken. Republicans hardly face any exposure: Even with prospective primary challenges, only Maine Sen. Susan Collins is even remotely at risk this cycle against a Democrat.  All told, the 2014 map is even more encouraging for Republicans, provided they land the right candidates.

Might 2014 be the year the Republicans win both the House and Senate? With Rockefeller's retirement, things look promising indeed.