Crossroads GPS, the shadowy conservative organization which former Bush White House aide Karl Rove helped found, has launched $1.8 million in advertising attacking five Democratic Senate candidates, including Elizabeth Warren in Massachusetts, according to the arm of the Democratic Party tasked with electing Democrats to the Senate.

The attacks come a full year ahead of the 2012 elections, in which Democrats will be defending their small Senate majority against a Republican onslaught.

Crossroads GPS, which spent heavily on attack ads in the 2010 midterm elections which helped defeat Democrats nationwide, is buying advertising against Democrats in Virginia, Montana, Missouri, Nebraska, in addition to Warren.

“Why Warren? Because she is a true fighter against corporate power and is a serious threat to beat Scott Brown and take back that seat in Massachusetts,” says Guy Cecil, executive director of the Democratic Senatorial Campaign Committee (DSCC).

A former adviser to the Obama administration, Warren has become the frontrunner for the 2012 Democratic nomination for Senate from Massachusetts by running a feisty, populist campaign.

She would oppose Brown, the Republican who won an upset victory in 2010 to fill the unexpired term of the late Democratic Sen. Ted Kennedy. Brown now seeks his first full, six-year term.

The Crossroads ad against Warren attacks her for her support for the ongoing Occupy Wall Street protests against corporate influence on government.

YOU CAN WATCH VIDEO OF THE CROSSROADS ATTACK AD AGAINST WARREN HERE:

Click here to view the embedded video.

Senate Democrats face a challenging political environment next year. They must defend 23 seats — more than twice as many as their GOP counterparts. A net loss of just four seats would throw the Senate majority back to the Republicans.

In an email Friday, the DSCC sought to raise $50,000 by midnight for what Cecil calls its “Year Out Project.”

“Every dollar we fall short is a dollar Karl Rove can spend attacking our candidates without challenge,” he says. “With 23 seats to defend, we can’t afford that. We would lose the Senate, and the new leadership would have Rove on speed dial.”

Scott Nance is the editor and publisher of the news site The Washington Current. He has covered Congress and the federal government for more than a decade.

Sen. Al Franken gave his endorsement to Elizabeth Warren's surging campaign for Senate in Massachusetts.

Elizabeth Warren picked up a key endorsement, and potentially a significant new fundraising source, in her campaign to take on Sen. Scott Brown (R-Mass.).

Warren, who is quickly solidifying her position as the frontrunner for the 2012 Democratic Massachusetts Senate nomination, won public support Tuesday from Sen. Al Franken (D-Minn.), the former late-night TV comedian and progressive talk radio host.

A former top adviser to the Obama administration, Warren entered a crowded field vying for the chance to take on Brown, the first Republican in a generation elected to the Senate from the Bay State. She has seen her standing soar in recent weeks, in large measure due to a popular online video in which she pushed back against conservative anti-tax and pro-corporate positions.

“We’ve all seen what Elizabeth can do with her smarts — and her guts. I’ve been impressed with her tenacity for years. She took on Wall Street before anyone else would and pushed consumer protection to the top of the financial reform agenda,” Franken says in an email to his national base of supporters. “We know she’s tough and fiery and even funny. We know she’s got a great life story and a full career of achievements fighting for middle-class families. That’s why progressives like you and me have been fans for a long time, and why we hoped she’d be able to lead the consumer protection board she created. And now, when we imagine her voice in the Senate, well, it’s even more exciting.”

After taking his Senate seat last year in a special election to fill the unexpired term of the late Sen. Ted Kennedy (D-Mass.), Brown in 2012 will be running for his first full, six-year term.

Warren’s field of competitors for the nomination to oppose Brown has begun narrowing in recent weeks, and a recent poll indicates that she not only erased Brown’s lead, but has pulled slightly ahead. The Massachusetts Democratic primary to select the nominee to face off against the incumbent will take place next September, just weeks ahead of the November general election.

Recapturing the seat which Kennedy held for decades as a prominent Democrat is a top priority for national Democrats who will face a tough year in the Senate overall. Senate Democrats will be defending more than twice as many seats as their Republican counterparts in 2012. A net loss of just four seats would allow the GOP to capture a Senate majority.

In his email, Franken acknowledges Warren will not have an easy time of it against Brown. He also appears willing to use his star power to solicit donations nationally for her campaign.

“Remember that just as excited as we are about having Elizabeth in the Senate, that’s how panicked the special interests are about the idea. They are going to spend millions trying to stop her — that was the headline in Politico. ‘Wall Street Readies Assault on Elizabeth Warren,’” Franken says. “We’ve seen far too many great Democrats get buried under attack ads, but we also know that big grassroots support can beat big money. That’s how we won in Minnesota — and that’s how Elizabeth can win in Massachusetts.”

Scott Nance is the editor and publisher of the news site The Washington Current. He has covered Congress and the federal government for more than a decade.