You can officially mark it down: February 1, 2007, the day the first real salvo was fired in the race for the U.S. Senate…in 2008.

As the Rocky Mountain News reports:

Rep. Mark Udall fired a warning shot in the 2008 U.S. Senate race on Thursday by co-sponsoring “anti-corruption” legislation that reminds people of a past controversy surrounding one of his potential Republican rivals, former congressman Scott McInnis.

Udall, D-Eldorado Springs, agreed to co-sponsor a bill by Rep. Phil English, R-Pa., to prohibit candidates or their immediate family members from drawing salaries from campaign committees for campaign-related work.

McInnis drew media scrutiny and complaints from Democrats in 2004 and 2005 over the tens of thousands of dollars his campaign has paid his wife, Lori, to work as campaign manager — including after he announced he would leave Congress to become a lobbyist.

Paying family members from campaign accounts is legal as long as the spending is for legitimate campaign work or expenses and it’s at market rates. The practice is relatively common in Congress, and several current or past Colorado lawmakers are among those who have paid family members from campaign accounts.

Still, none of the other Colorado cases comes close to the more than $145,000 that Lori McInnis was paid from 2001 to 2005.

McInnis and Udall are the two known candidates for the U.S. Senate seat being vacated by Republican Wayne Allard in 2008, and Udall made a smart move today by going after McInnis early. The issue of McInnis using his campaign warchest to pay his wife for work long after he was actually a congressman may or may not have legs, but by introducing this bill, Udall is doing what he can to keep the issue alive.

In the meantime, 2004 Senate candidate Bob Schaffer is expected to soon announce his intentions to run in 2008, joining McInnis in what could be a hard-fought GOP primary for the third straight election cycle (Pete Coors defeated Schaffer in a 2004 primary, and Bob Beauprez kept Marc Holtzman out of the 2006 primary for governor).

Udall will probably get this race to himself on the Democratic side, both because there are no obvious candidates who might challenge him and because he would be very difficult to defeat in a primary. Udall is well-known and well-liked by Democrats around the state, which will make any potential challenger think twice. In fact, the only way another Democrat might run is if Udall decided not to run, which isn’t entirely out of the question given that he backed out of a Senate race once before (in 2004).

While 2008 is still a long way ahead, I think the field for the U.S. Senate may already be set. Another Republican candidate isn’t likely to join a field of McInnis and Schaffer, and Udall has been giving more public indications that he is indeed serious about running in 2008. There is a lot of money to be raised and a lot of barbs to be fired until November 2008, and the first one was launched today.