On Wednesday President Obama will begin the first of two days of meeting with Senators, a first public step in what is expected to be a contentious negotiation over increasing the debt ceiling.

Obama meets with Senate Democrats today; on Thursday he will sit down with Senate Republicans.

Looking for signs as to whether Obama’s message on the debt is working? Below are five key Democratic Senators to keep an eye on today and for the remainder of the debt debate. Tomorrow, we’ll bring you a look at five key Republican Senators to watch.

* Dick Durbin: Durbin may be the most cross-pressured Democratic in the Senate. On the one hand, he is a member of the “Gang of Six” working to translate the recommendations of the President’s debt commission into actual legislation. On the other, he is an avowed liberal and the second ranking Democrat in the Senate. Should he move to far to the middle on any budget plan, Durbin would almost certainly face some backlash inside and outside the chamber from liberals. On even another hand — yes, you can have three hands in debates this complicated — Durbin is a homestate ally of President Obama and doesn’t want to get publicly crosswise with his one-time colleague on such a critical fight.

* Claire McCaskill: The Missouri Senator has been one of Obama’s leading advocates — in the Senate and on the cable television circuit — since she won the Show Me State seat in 2006. But, McCaskill is a major Republican target as she seeks a second term in 2012 and Missouri has a clear conservative tilt to it. It would behoove McCaskill politically to put some space between herself and Obama on a high-profile issue like debt reduction. Moreover, McCaskill is co-author with Sen. Bob Corker (R-Tenn.) of a bill that some Republicans have privately signaled is their potential middle-ground point on deficit reduction in order to lift the debt ceiling. But, will her friendship with and loyalty to the President trump electoral concerns?

* Patty Murray:Murray serves in two powerful roles — chairwoman of the Democratic Senatorial Campaign Committee and as the second-most senior member of the Senate Budget Committee. Senior Democratic Senate aides acknowledge that for the deficit reduction push to build momentum in the chamber it needs the support of a veteran member (or two) with a generally liberal ideological profile. That’s Murray. One complicating factor: She is also a member of the Senate Appropriations Committee and voted against the first two continuing budget resolutions.

*Mark Udall: Udall represents Colorado — one of the swingiest states in the country — and has been an outspoken voice publicly and privately about the need to get something done to reduce spending and the debt. (Udall has introduced a balanced budget amendment along with Alabama Republican Sen. Richard Shelby.) In the words of one senior Democratic aide, Udall is “looking for something to be ‘for’” and, as such, could be an up-for-grab vote for Democrats and Republicans.

* Mark Warner: Warner is also a member of the “Gang of Six” but far more centrist in his ideological profile than Durbin. Warner is also heavily invested in producing some sort of plan after months of meetings and is likely to very skeptical of other efforts to push the Gang plan aside. And, Warner, who weighed a 2008 presidential run before running for the Senate in Virginia, has the sort of national profile that could either boost or undercut Obama’s efforts at rallying Democrats behind a debt plan.

Sanchez in Texas Senate race: Retired Gen. Ricardo Sanchez will run for the open Senate seat in Texas next year, according to a Democratic source close to the campaign.

Sanchez, who Democrats have been working to recruit, plans to make his announcement on Facebook later today. He has an interesting background that could both help and hurt in the campaign — he was the top military commander in Iraq when the Abu Ghraib scandal effectively ended his military career. He went on to become an outspoken critic of the Bush Administration.

Democrats think they have a shot at the seat held by retiring Sen. Kay Bailey Hutchison, thanks to changing demographics in the state (38 percent of Texans are now Hispanic).

But turnout among Latinos is low, and those that do vote are not always voting Democratic — 38 percent voted Republican in 2010. National Republican Senatorial Committee spokesman Brian Walsh points out that President Obama is none too popular in the state: “So we’ll leave it to national Democrats to crow about their latest hand-picked candidate because as any observer of Texas politics knows, we’ve heard it all before and we have no doubt this seat will remain in Republican hands.”

NY-26 ads out: American Crossroads and the National Republican Congressional Committee have released their ads in the NY-26 special elections. The NRCC ad is web-only.

Neither ad mentions the Democratic or Republican candidates. Instead, they target Tea Party candidate Jack Davis, a millionaire gadfly who ran for the seat as a Democrat three times in the past.

You can see the ads here and here.

FixBits:

Jon Huntsman is planning a five-day trip to New Hampshire with about a dozen stops.

Rep. Todd Akin (R-Mo.) told Missouri Republicans that he’s going to announce his Senate campaign against McCaskill next Tuesday.

Iowa Republicans expect Rep. Michele Bachmann (R-Minn.) to announce her presidential campaign on May 26.

Rep. Mike Pence (R-Ind.) has a long-shot gubernatorial primary challenger.

Must Reads:

Romney focused on outraising — by far — Republican presidential competitors ” - Dan Eggen and T.W. Farnam, Washington Post

Is Cheri Daniels ready to take the plunge?” - Jon Murray, Indianapolis Star

Humbled Gingrich talks about his mistakes” - Ralph Z. Hallow, Washington Times