The entire Southwest is primed for turnover in 2012.

Recent Senate retirements in Arizona and New Mexico and competitive races in Nevada, coupled with growing populations, have elevated the Wild West to be the next major political battleground.

The region will play a decisive role in Democrats’ ability to hold their Senate majority.

Within a week, New Mexico and Arizona moved from likely Senate seat holds for each party to potentially highly competitive races, and they could both result in the vacancy of at least one House seat.

More turnover in the Southwest is expected in Nevada, where Sen. John Ensign (R) will face tough challenges from both parties, and Texas, where Sen. Kay Bailey Hutchison (R) is retiring.

Nevada Reps. Dean Heller (R) and Shelley Berkley (D) are looking at Ensign’s seat and are widely considered favorites over the ethics-plagued incumbent. Their bids would open up two House seats in Nevada to go along with the seat that the state will gain through reapportionment, making three of the state’s four districts open-seat races.

A large pool of Republicans are vying for Hutchison’s seat, and the political intrigue in Texas will largely be centered on that primary. But the Lone Star State is also adding four districts through reapportionment, and Democrats are looking to take back a couple of House districts lost last year.

Add in what are expected to be competitive re-election bids for Sens. Ben Nelson (D-Neb.), Jon Tester (D-Mont.) and Orrin Hatch (R-Utah), plus the race for the open Democratic seat in North Dakota, and it is clear there will be plenty of 2012 action west of the Mississippi.

Democrats were successful in two vulnerable Western states last cycle. Senate Majority Leader Harry Reid (D-Nev.) and Sen. Michael Bennet (D-Colo.) overcame a challenging nationwide landscape for Democrats and an active political force in the tea party.

“The open seats out West really raise the stakes for us now,” said a knowledgeable Democratic source with extensive experience in the region. “The Latino vote in all three states [Nevada, Arizona, New Mexico] will be vital for Democrats. We saw what it did for Bennet and Reid in 2010, and we’ll need to find a way to successfully replicate those efforts across the region in 2012.”

President Barack Obama also broke into the West en route to his 2008 victory, including wins in Colorado, Nevada and New Mexico after each voted Republican four years earlier. With Sen. John McCain (R-Ariz.) off the ballot in 2012, Democrats want to expand the electoral map to Arizona as well.

Republicans are sounding confident about their chances when it comes to the Senate, getting a boost in recent weeks by top recruits jumping in and Democratic retirements.

That is especially true in New Mexico, where Sen. Jeff Bingaman (D) announced Friday that he will retire at the end of his fifth term rather than seek re-election, opening yet another Democratic seat ripe for the GOP’s picking. Roll Call Politics shifted its ranking of this seat from Safe Democratic to Tossup.

Sen. Jon Kyl (R-Ariz.), the Minority Whip, said a week earlier that he will leave at the conclusion of his third term, but the seat at this point looks to be a safer bet for the GOP. Roll Call Politics rates that seat Leans Republican.

After the first month of the cycle, Democrats have $2.65 million in cash on hand while carrying $8.8 million in debt. Republicans are on similar financial footing as of the end of January, with $432,000 in the bank and $6.5 million in debt.

While both committees are climbing out of the red, Republicans are cruising early in the cycle on a series of strong recruits with fundraising chops. Former Sen. George Allen (Va.), Rep. Denny Rehberg (Mont.) and Nebraska Attorney General Jon Bruning all give the GOP legitimate shots at those Democratic seats.

That streak continued when Rep. Jeff Flake (R-Ariz.) immediately announced he would run for Kyl’s seat, giving the GOP an instant top-tier candidate in Republican-leaning Arizona.

“It speaks volumes about the state of the two political parties that as strong Republican candidates step forward in key races, Senate Democrats in important battleground states are stepping aside,” National Republican Senatorial Committee spokesman Brian Walsh said Friday in the wake of Bingaman’s retirement announcement.

While it is still early in the cycle, Bingaman’s retirement puts the Democrats’ hold on the Senate in an even more tenuous position than it was already. With a 53-47 majority, there are now enough open and competitive seats for Republicans to at least make the Senate an even split.

Along with New Mexico and North Dakota, where Sen. Kent Conrad is retiring, Democrats are looking for candidates to defend an open seat in Virginia, with Sen. Jim Webb announcing his retirement a couple of weeks ago.

Democrats actually improved their standing in Connecticut with the retirement announcement of Sen. Joe Lieberman (I) in January. They will be favored there, as well as in neighboring New York, where Sen. Kirsten Gillibrand (D) is running for a full term, but the party will have a challenge to the north against Sen. Scott Brown (R-Mass.).

One Democratic source said the early retirements are part of a Democratic Senatorial Campaign Committee strategy to push Senators to announce their intentions sooner rather than later, avoiding a scenario the party faced in Indiana last cycle when Sen. Evan Bayh (D) waited until the deadline to retire.

“The timing of these aren’t incidental,” the source said.

That leaves questions surrounding Democratic Sens. Daniel Akaka (Hawaii) and Herb Kohl (Wis.), who each have signaled they want to seek another term. But Akaka, 86, and Kohl, 76, remain retirement possibilities. Republicans have made it clear that they would aggressively target both states.

The Democrats will also have tough holds in states such as Florida, Missouri and Ohio — all have incumbents running and each receive plenty of attention in presidential election cycles.