By Emily Cadei, CQ Staff

Vulnerable Republican senators are not going to go quietly into the 2008 election, if their fundraising last year is any indication.

The 15 vulnerable GOP incumbents, according to CQ Politics’ race ratings, flexed some significant money muscle in 2007, out-raising their Democratic challengers and spending heaps of cash as they sought to create a bulwark against the Democrats’ advances.

And they found common ground with their colleagues in similarly competitive seats – many of them donating thousands of dollars to each others’ races.

“When we came in to this election cycle we were very specific with our candidates who were in more vulnerable seats,” said Rebecca Fischer, communications director with the National Republican Senatorial Committee (NRSC), the fundraising committee for the Senate GOP. “[Fundraising] needs to be taken seriously and there needed to be a big push from the very beginning.”

Republican senators appear to have heeded the warning. The four most at risk, Sens. Susan Collins of Maine, Norm Coleman of Minnesota, John E. Sununu of New Hampshire and Gordon H. Smith of Oregon, all started pulling in large sums in donations early in 2007 and they continued throughout the year.

Coleman is girding for an expensive battle against either Democrat and former Saturday Night Live comedian Al Franken or Mike Cerisi, a wealthy lawyer who is best known for taking on tobacco companies. Coleman raised $10.5 million in 2007, one of the highest tallies among senators last year. Smith raised $7.2 million as he prepares for the winner of a crowded Democratic primary. Sununu and Collins both reported more than $4 million in receipts.

A second set of GOP senators in seats being eyed by Democrats but rated by CQ as “Republican Favored” have also been busy beefing up their bank accounts in hopes of deterring a serious challenge.

Of the 11 members in this category, Republican Conference Vice Chairman John Cornyn of Texas and Minority Leader Mitch McConnell of Kentucky led the way with $12.6 million and $10.9 million, respectively. Only two – Wyoming Sen. John Barrasso and newly appointed Mississippi Sen. Roger Wicker – raised less than $2 million last year.

Helping boost all 15 Republicans’ totals were donations from those who can empathize best – fellow vulnerable Republican senators. Coleman, for example, received contributions totaling $55,000 from the political action committees (PACs) run by McConnell, Sununu, and Sens. Ted Stevens , R-Alaska, Jeff Sessions , R-Ala., James M. Inhofe , R-Okla., Saxby Chambliss , R-Ga., and Lamar Alexander , R-Tenn., all of whom face the prospect of competitive races this fall. Coleman’s PAC, in turn, gave $5,000 each to Sununu and Collins, and $10,000 to Smith. Sununu received $30,000 total from other vulnerable members, while Collins banked $85,000 and Smith $50,000.

Under federal election law, PACs can donate no more than $10,000 to a given campaign, including their own. Politicians often raise money for their PACs to disperse to other candidates they support, and to improve their standing with colleagues.

For Republican incumbents, it’s not just about raising cash but building an organization early that gives them an insurmountable edge later on. To that end, they’ve been spending freely in the off-year as they open campaign offices, hire staff and host events, many of them to raise more money.

On average, Republican senators in competitive races spent $2.6 million last year, one million more than the six vulnerable Democratic senators, who averaged $1.6 million in disbursements.

Sen. Elizabeth Dole , R-N.C., topped the pack, shelling out $5.7 million in 2007, with Cornyn and Coleman next at $5.2 and $4.5 million, respectively. The highest spending Democrat in a competitive race was Sen. Mary L. Landrieu of Louisiana, who reported $2.7 million in expenditures.

Democrats say their candidates are just getting started and they have time and national political currents on their side.

Democratic Senatorial Congressional Committee (DSCC) spokesman Matt Miller noted that most of the Democratic challengers in these races did not kick-off their candidacies until the summer or fall, giving them less time to raise money last year.

Miller pointed to the last six months to get a better sense of the financial prospects for Democrats in these competitive races.

“If you go down the list, Franken out-raised Coleman in each of the last two quarters. In New Hampshire, [former Gov. Jeanne] Shaheen out-raised Sununu in the last quarter. In Maine, [Rep. Tom] Allen has really kept pace with [Collins].”

Miller also downplayed the significance of Republicans spending advantage. “If you look at last cycle, Democratic challengers knocked off six Republican incumbents and in each of those six states the challengers were outspent,” Miller said.

For Republicans, building a cash advantage could be even more critical this year given the fact that the NRSC badly trails the DSCC in fundraising, and will likely have less cash to disperse to its candidates in the coming year. At the end of 2007, the Democrats reported $29.4 million in cash on hand while their Republican counterpart had only $12.1 million.

Fischer said fundraising successes of Republican incumbents in these races “certainly makes our job easier over time.” But she added that that did not alleviate the imperative that NRSC boost its coffers in 2008.

“It takes zero pressure off of us.”