While Gallup reports that the pool of likely voters hasn’t changed much over the past month, Politico reports that another measure keeps increasing: the number of Democratic seats at risk in the election.   Suddenly, instead of just the Blue Dog seats that Rahm Emanuel worked hard to win in 2006, the midterms are putting a number of traditionally Democratic seats on the watch list, too.  The expansion of the field plays well for Republicans, who have more ammunition and more resources than Democrats playing defense:

Freshman Democrats make up a large share — more than a quarter — of those facing competitive races. Of the 38 Democrats serving their first full terms in the House, POLITICO rates 29 as at-risk. Some — such as Reps. Bobby Bright of Alabama, Betsy Markey of Colorado, Alan Grayson of Florida and Frank Kratovil Jr. of Maryland — hail from GOP-friendly districts, where they have been in the cross hairs almost since the moment they were elected.

But legislative vets are under fire too. Nine-term New York Rep. Maurice Hinchey and four-term Arizona Rep. Raul Grijalva until recently were considered near-locks to win, before their campaigns hit unexpected turbulence. Hinchey attracted unflattering attention this weekend after a videotaped confrontation with a reporter at the same time American Crossroads and other GOP groups are pouring hundreds of thousands of dollars into ads in his district.

Grijalva, who called for an economic boycott of his own state amid a housing crisis and record unemployment, has also been hit by outside spending right after an automated poll unexpectedly showed him in a dead heat with his GOP opponent.

The list also includes a handful of veteran Democrats who typically enjoy the benefits of seniority on Capitol Hill and cruise to reelection but this year find themselves locked in competitive races. Among those Democrats are Armed Services Committee Chairman Ike Skelton of Missouri and Budget Committee Chairman John Spratt of South Carolina.

Getting outhustled in fundraising is another way for candidates to find themselves on the bubble.

In a sign of GOP momentum — and of the breadth of the competitive landscape — at least 40 Democratic incumbents were outraised by their GOP challengers in the most recent quarter, according to FEC filings. Reps. Ron Klein of Florida and Stephanie Herseth Sandlin of South Dakota, both stellar fundraisers, were among those outraised in the latest reporting period.

Politico sees 99 Democratic seats in play, which would put Republicans in position for a win on a scale not seen in decades.  Charlie Cook says it looks like a 52-seat rout along the same lines as 1994, but that would be just barely over a half-and-half split of endangered seats.  Democrats may be hoping for 52 seats as a floor at this point in time.

Part of the problem is money.  While Democrats have raised more in their party organizations, money has poured into conservative political action committees around the country.  Unions usually fill the gap, but voter anger has outpaced union organization in this cycle.  That’s because the bigger problem isn’t money at all, but the sorry economic record of Democrats after four years in control of Congress, and of Obama himself after two years in the White House.  Instead of bolstering an environment of economic growth, Democrats have used the crisis as an excuse to fund hobby-horse social-engineering projects, expand government authority, and spend like drunken sailors.

Small wonder, then, that members of leadership like Skelton finds himself in deep trouble in a relatively balanced district.  James Oberstar couldn’t even get more than a single contribution to his campaign from inside his district in the entire third quarter.   John Spratt once claimed in 2006 that a failure to produce a complete budget was a disqualification for control of Congress, but four years later his party couldn’t even produce a budget resolution in a chamber they controlled by 77 seats.  Grijalva’s problems are more local; after calling for an economic boycott of his own state, his constituents want someone who isn’t actively trying to kneecap local businesses.

In this cycle, don’t be terribly surprised if 99 turns out to be a conservative number, in more ways than one.

Update: Jim Geraghty says all the cool kids are talking about 117.