In even a neutral political environment, the 2014 midterms were going to be a challenge for Senate Democrats. They are defending 21 seats to the GOP’s 15, with only two of the Republican seats at any kind of risk of flipping to the Democrats. Moreover, Democrats were defending many freshman Senators who first won office in in Republican states in Obama’s wave election in 2008.

This isn’t a neutral political environment, however. Obama’s low approval ratings, the continued fallout over ObamaCare, current Democrat happy-talk notwithstanding, and the sluggish economy have provided Republicans with an enthusiasm and turnout advantage that could match 2010.

A recent USA Today poll found that those opposed to ObamaCare were more enthusiastic about voting this November. In addition, a recent AP poll found that, since Obama’s reelection, there was been a 10-point swing towards Republicans in voter self-identification. Today, 41% of voters consider themselves Democrat or Democrat-leaning, while 39% now say they are Republicans. Democrats had a 12-point advantage at the end of 2012.

The Republicans need to pick up 6 seats to take control of the Senate. The party appears half-way there, with almost certain wins in West Virginia and South Dakota and a big advantage in Montana. Until recent months, most observers assumed that control of the Senate would rest on four deeply-red states; i.e. Alaska, Arkansas, Louisiana and North Carolina. Under that scenario, the GOP would need to win three of those four contests to take the majority.

In recent weeks, however, the Senate battleground has expanded at the expense of the Democrats. Democrat retirements in Iowa and Michigan have made those states very competitive. A recent poll in New Hampshire, which is home to many transplants from Massachusetts, put former GOP MA Sen. Scott Brown just six points behind incumbent Dem. Sen. Jeanne Shaheen. In Colorado, popular GOP Rep. Cory Gardiner is challenging freshman Dem. Mark Udall in the swing state.

The Democrat party is on the defensive in Colorado after two Democrat state Senators were ousted in recall elections last year as a result of their push for gun control. A third Democrat state Senator facing recall resigned, as her ouster would have given Republicans control of the state Senate.

These developments essentially double the pool of seats from which Republicans need to net three pick-ups. Unfortunately for Democrats, this pool could expand even more.

Republicans are now eyeing Oregon, which experienced its own disastrous roll-out of the state’s health exchange, as a pick-up opportunity. The GOP has a contested primary to nominate a candidate to challenge freshman Dem. Sen. Jeff Merkeley, with Dr. Monica Wehby, a pediatric brain surgeon, appears the front-runner.

The GOP is also increasingly optimistic about its chances in Minnesota where freshman Sen. Al Franken faces reelection. Franken won his seat by a few-hundred votes at the same time Obama won the state by a large margin. If Minnesota is in the mix of competitive states in October, then Democrats can expect a very long night in November.