Nevada Rep. Shelley Berkley entered the Silver State's 2012 open Senate race to replace retiring Republican John Ensign today with the Democratic Senatorial Campaign Committee's endorsement in tow.

DSCC Chair Patty Murray explained that she is endorsing in the race because it's a Republican seat that the party is trying to flip, and she does not expect that Berkley will have a competitive primary even though other candidates are eyeing the race. In a briefing with reporters today, Murray said that she is poised to endorse candidates in other races as she sees fit, too, because she does not expect to receive the same kind of backlash the National Republican Senatorial Committee experienced from activists last cycle when it tried to handpick candidates and wound up with several tea party-inspired candidates instead.

"I don't have the NRSC's problem. I don't have bloody primaries in half of our tough races," she said. Pressed on whether the DSCC could have the same fate by forcing the establishment on individual states, she said, "I am not playing in their field. They've got a tough game that I'm just happy to watch."

NRSC spokesman Brian Walsh responded to Murray's point by noting, "It speaks to the desperate straits facing Senate Democrats that they think the only thing standing between them and losing the majority are GOP primaries, instead of an agenda that's supported by most Americans." He added, "But when you look at key races across the country, including Massachusetts, Indiana, Maine and Texas, which they claim to be targeting, the Democrats would be so lucky as to have a primary considering they can't yet field any candidates."

New Mexico, for example, could become tough to hold with former Rep. Heather Wilson leading the GOP field in the open race to replace retiring Democrat Jeff Bingaman. Democratic Rep. Martin Heinrich is a favorite of Murray's, who said she may still endorse the two-term congressman but is under less pressure this early in the cycle because her party holds the seat.

The Nevada race could be tougher than that -- even though Majority Leader Harry Reid won the state convincingly last year, and the state's trend lines have been favoring Democrats -- because the GOP won a recruitment coup in luring Republican Rep. Dean Heller into the race, forcing the Democrats to ramp up early.

And Nevada is among Murray's "six in '12," a group of six states with Republican-held Senate seats that the Democrats are targeting aggressively for next year's races as they try to hold their majority. The other five seats are in Arizona, Indiana, Maine, Massachusetts and Texas.

While she wasn't ready to give details about Arizona in deference to Democratic Rep. Gabby Giffords' family in the wake of January's tragedy and the congresswoman's recuperation from a gunshot wound, Murray vowed that the party will have a candidate to take on the Republican nominee vying to replace retiring GOP Sen. Jon Kyl. She pointed out that President Obama may make the state competitive in 2012 and would have in 2008 had the home-state senator, John McCain, not been his opponent on the ballot.

Most important, she said, "What happened to Gabby Giffords changed the political landscape of Arizona."

And like in Arizona, Murray said the open-seat Senate race in neighboring Texas is competitive due to changing demographics. Murray didn't have a candidate to name but suggested one if forthcoming.

Maine and Massachusetts feature two wildly popular Republican incumbents -- Olympia Snowe and Scott Brown, respectively -- but because they are moderates in blue states, they face the prospect of tea party primary challenges that could end their candidacies before Election Day.

As for Indiana, she also pointed to the tea party, which is looking to end veteran Republican Dick Lugar's distinguished Senate career. Recalling tea party favorite Christine O'Donnell's surprise victory over veteran House Republican Mike Castle in Delaware's September primary last year, she suggested asking freshman Delaware Democratic Sen. Chris Coons why he is a senator today.

"I really like Senator Lugar," she said, calling the Hoosier a personal friend, but she said her job dictates that because he appears poised to lose his primary to Indiana Treasurer Richard Mourdock, she has to come up with a Democratic candidate in the event that Mourdock is the GOP nominee. An announcement from Democratic Rep. Joe Donnelly about whether he will run for the seat or not is expected soon.

As for the 23 seats Democrats are defending, Murray said she expects that all of the incumbents who have not announced retirements are running at this time -- even though questions still lurk about Wisconsin Sen. Herb Kohl's commitment to running for a fifth term.

And regarding one of the toughest seats Democrats have to defend -- Missouri Sen. Claire McCaskill's -- Murray argued that the first-term senator has shown strength in the face of adversity when she got pummeled last month for having failed to pay taxes on her husband's private plane.

"She McCaskilled it," Murray said, adding, "I don't see damage with it." Murray pointed out that it was McCaskill who demanded an investigation into the matter right away, and she noted that she attacked the problem the same way the Missourian has gone after line-items in the budget that she doesn't like.

And Murray, who quickly and deftly handled the McCaskill questions, did the same for a handful of other grenades tossed at her. The four-term Washington State senator, who once identified herself as a mom in tennis shoes, revealed herself in her DSCC press debut to be a sharp messenger for a party looking to dig itself out of what was a tough election cycle in 2010 and facing what appears to be a challenging landscape in the coming cycle.

After noting that the session was termed a "pen-and-pad" for the reporters' utensils, she quipped, "I would exchange those for pencils. This is the kind of election where you're going to have to erase what you wrote three months ago -- and probably throughout the cycle -- because I know better than anybody how races form...and change up dramatically in the months of a real election cycle, and this is no different."

She does have some experience. She looked like a lock for re-election in 2010 until Republican Dino Rossi entered the race with five months to go until Election Day last year. She suddenly found herself in one of the country's tightest Senate races and ended up prevailing by less than 4 percent. Across the board, Democrats appeared poised to add to their supermajority as the 2010 cycle began but later wound up in danger of losing even a simple majority as the cycle wore on.

Murray figured that the trends are shifting and are going to start heading in the direction of Democrats. Among the sticking points against Republicans, she said, is House Budget Committee Chairman Paul Ryan's blueprint for the budget and the way the GOP negotiated last week's last-minute shutdown crisis.

She noted that Republicans pressed Democrats to cut more out of the budget, but that the GOP showed at the last minute that cutting funding for Planned Parenthood was paramount.

"It wasn't budget cuts. It was an attack on women's health," she said. "Now that was visible in this country, all the way to the talk shows, which continues."

She panned the Ryan budget as an assault on the middle class and offered a specific example of how they will use their messaging to attack individual Republicans. In Montana, for example, she pointed out that Republican Rep. Denny Rehberg recently likened Pell Grants for college students as a form of welfare.

"If you don't think that doesn't resonate through the Internet and on college campuses and generate enthusiasm on our side, you haven't been online," she said.

As a consequence of episodes like that, Murray said she's seen a major uptick in the committee's online fundraising -- 350 percent, in fact, higher than the committee's rate in 2009. She also noted that changing polling trends bear out that the public is returning to favoring Democrats.

"I fully expect the president to win re-election. He energizes voters. He's done it before, and he will do it again," she said of the cycle, adding that a good night for Senate Democrats would be to hold onto their narrow Senate majority, which she believes they can do thanks in part to the president's turnout efforts and ability to energize young voters.

But before she launched into half an hour of drilling her message, she noted that her daughter was about to head into labor and she might have to dash out at any minute, saying: "I don't care what you write, because the first woman president of the United States is about to be born, and I'm going to be there."