Early voting opens in Iowa today, and Republican operatives are touting the endorsement Senate candidate Joni Ernst has gotten from the next-door neighbor of her opponent, Bruce Braley. The neighbor’s chickens had a habit of crapping on the congressman’s lawn, and Braley reacted. Republicans say the whole thing shows what a jerk Braley is. And in a race this close, chicken crap could actually decide the election, and thus control of the Senate, and thus the path of the entire United States government for the next two years.

All this illustrates something about this cycle: Republicans don’t need an agenda to win. And it’s a good thing for them, because with barely more than a month to go, they certainly aren’t going to come up with one.

This morning, Karl Rove advised Republicans that “it is not enough for Republicans to remind them of Mr. Obama’s many failings; voters want to know how the GOP would move the country forward.” Here’s the Wall Street Journal from earlier this month: “Especially as Election Day nears and disengaged voters pay attention, Republicans need to show voters what they’re for.” Here’s Ramesh Ponnuru telling Republicans that if they don’t come up with a positive agenda, they could lose like they did in 1998. Here’s Newt Gingrich telling Republicans the same thing. Here’s Erick Erickson agreeing.

Just a few months ago, Republicans were talking about coming up with a Contract With America for 2014, a new document that would explain their forward-thinking governing vision to voters (sure, they didn’t follow through, but their hearts were in the right place).  This is something we hear in every midterm election, from both partisans and neutral observers alike. You have to tell Americans what you’re for!

Wrong.

The idea rests on the assumption that to actually win the election, voters must have a clear idea of what you’re for, because only then will they vote for you. But look at recent midterm elections. Every one in the last two decades years was a dramatic victory for one side or the other. Republicans took back Congress in 2010, dealing a stunning blow to Barack Obama. Democrats did the same thing in 2006. Republicans bludgeoned Democrats in 2002, with the aftermath of 9/11 upending the traditional win for the opposition. Four years earlier, Democrats managed the same kind of upset, with the Clinton impeachment debacle turning voters away from the GOP. In none of those cases was the outcome determined by some positive agenda for governing.

All were primarily negative campaigns won for negative reasons. In 2010 and 2006, voters were mad at the president. In 2002 voters were just terrified, and in 1998 they were disgusted with the Republicans.

Ah, you say, but what about the original Contract With America? Wasn’t that inspiring document the surfboard of glory on which Newt Gingrich and the Republicans rode to victory in 1994? No, it wasn’t. Polling before the election showed that few voters had the faintest idea what it was.

It is sometimes said that parties need a “positive agenda” so that they have a template for governing — something around which they can claim a “mandate” once they win. But there’s no reason to believe that’s true, either. The fact is that once a party has control of one or both houses of Congress, it will do whatever it is going to do, regardless of whether it has whatever it is we call a “mandate.” Every election winner acts as though they have one, whether they campaigned on a “positive agenda” or not.

It may be helpful for a particular candidate to show her voters that she’s got shiny new ideas about where the country should go. But overall the party will do just as well (or as poorly) whether they have an agenda or not. Consequential policy issues like whose chickens crapped on whose lawn could actually be enough to help swing the Senate this time.