Americans For Prosperity, the Koch-founded conservative PAC, is running $2.5 million worth of ads against three Senate Democrats focusing on Obamacare. Why now, in January 2014? Three reasons: They have the law, time, and a big bank account on their side.

AFP, as it's known, had a bit of a rocky year in 2012. It spent $122 million, largely hoping to prevent the reelection of Barack Obama. That didn't work. It also spent vast amounts of money on ads on other races, like trying to stop Tammy Baldwin from winning a Senate seat in Wisconsin (she did anyway) and Bob Kerrey from retaking his in Nebraska (he didn't.) And now their $2.5 million is hitting Sens. Kay Hagan from North Carolina, Mary Landrieu from Louisiana, and Jeanne Shaheen in New Hampshire. (The ad against Shaheen is at right.)

AFP is a 501(c)(4) non-profit, meaning that there are restrictions on when and how they can directly advocate for political candidates. Which is reason number one that they're running ads now: There isn't any official race underway. If you watch that ad above, you'll notice that the request isn't to vote against Shaheen — it's just to call Shaheen and tell her you're disappointed in her. Obviously that's not actually what AFP expects voters to take away from the ad; the organization's press release about the ad buy says they're "putting pressure on senators" who echoed President Obama's "if you like it, you can keep it" argument. It's about "accountability," they say, not about pushing the senators to vote for particular legislation.

Then there's the timing. First, the timing works because AFP has an issue it can hammer. Obama's claim was named the "lie of the year" in 2013, and Obamacare is still a potent political topic. If you're going to hit Democrats on something right now, Obamacare is about as good as it gets. But the timing also works from a political perspective. If you're hoping to unseat a candidate, the longer you can hammer their record and candidacy, the better. The campaign of each senator's Republican opponent will do that this summer and fall — but no one else is going to have the money to do it now. After all, no Republican candidate campaign even exists at this point. Campaigns often hope that independent groups will step in to attack during what would otherwise be a campaign dead zone. AFP is stepping up. And AFP can also help set the tone for the upcoming Republican primaries in New Hampshire and North Carolina. (Louisiana doesn't have party primaries.)

But most of all, AFP has money to burn. How much money isn't public knowledge, but it's enough to drop $2.5 million on ads eleven months before a general election. By running ads now, AFP is also spending that money wisely. Costs for airtime and production are lower now than they will be once those resources start getting constrained closer to the election. And the ad above could probably be used later in the campaign; since it avoids a direct call to vote for or against a candidate, it could likely be repurposed once the general election gets underway. The ad is already in the can, AFP would just need to buy more airtime.

The only outstanding question then, is this: Will this work? Will AFP's early investment actually help the group oust these three senators? Senator Baldwin and President Obama might have an opinion on that.