Today’s campaign finance news is that Mitt Romney raised…wait for it…$170 million in September. That’s 170,000,000 dollars. In one month. Oh, and he didn’t quite match Barack Obama, who raised $181 million that month.

So my question is simple. Why are you giving to them?

To be sure there are reasons to give to candidates other than to help elect them. You might want to attend a fundraiser and shake the candidate’s hand, and consider the price of admission reasonable. You might want to impress your boss with your dedication to her favorite candidate. You might be part of a group (or you might be a single individual) able to give enough to get the campaign’s attention, and try to use that to affect the candidate’s position on public policy.

But if you want to affect elections, and through them public policy, why give to the presidential candidates?

Unless you happen to be Sheldon Adelson, the amount you’re giving to Romney or Obama is just an infinitesimally tiny drop in the ocean. The odds are fairly good that diminishing returns mean that a large percentage of that haul will be wasted anyway. Not to mention that presidential elections are heavily covered by the press, which means that the information conveyed in ads isn’t all that important.

And yet, control of the Senate hangs on the results of a dozen or fewer elections in which far less money is being raised and spent. If you’re a Democrat, you can support Heidi Heitkamp in North Dakota, who announced today that she raised $3.7 million for the three months ending with September. Okay, that’s still a large total, but one in which your $50 or $5000 or whatever might actually be meaningful. If you’re a Republican, odds are that Richard Murdoch in Indiana could use your help. Here’s National Journal’s list of key Senate races; here’s their list of House elections most likely to flip seats. Twenty minutes of research will find you an excellent candidate who deserves, and could really use, your support.

Granted, a president is far more important than any single Senator, or even majority control of Congress. And it is true that some presidential campaign spending, such as get-out-the-vote efforts, will benefit the whole ticket. But the bottom line here is that anyone who wants to change the way the nation is governed is crazy to give anything at this point to the presidential campaigns. The next dollar contributed will be far, far more meaningful when given to House and Senate candidates, would-be state legislators, even ballot measures advocacy groups. Anything but the candidates who really don’t need your money.