If you’re planning on making political donations this year, and you really want your money to help the cause, here’s what you should do: Instead of sinking cash into either presidential campaign, put it where it will really matter — into Congressional or state and local races.

Here’s why: The battle for the House and Senate may well shape up as toss ups, which means that control of Congress is hanging in the balance. This matters just as much, and in many ways more, than control of the White House. The least bang for your buck comes in presidential general elections. Your money will make a much bigger difference in practically every other type of election.

If you’re a typical donor of the $25, $100, or even $5000 variety, your money is just a drop in the ocean of the hundreds of millions of dollars that both sides are going to spend on the presidential election. But more importantly, what we know about voter behavior suggests that money is least important in presidential (general) elections. Money matters more in nomination fights — where the candidates share a party label — than in general elections, where most voters will use the party label as a powerful cue. Moreover, voters will pay less attention to information they hear through paid advertising when there is plenty of other information available, as is the case with high-profile presidential elections. Add it all up, and your money just matters more — a lot more — in lower profile contests.

If you’re a partisan, that probably means finding the most competitive House and Senate races, or state and local races, and investing your money in those. If you are ideologically driven, that may mean getting involved in primaries. I’d recommend that liberals find nomination battles with clear liberal vs. moderate lines in states or districts where Democrats should win easily in November. A classic example right now would be the matchup between moderate Ed Case and liberal Mazie Hinoro for an open Senate seat in Hawaii. For more ideas, see ActBlue.

The final point: As critical as presidential elections are — and no doubt they are the single most important individual elections in US politics — control of both the House and the Senate in some ways can matter even more. After all, presidents only get the legislation that Congress produces; presidents can’t even staff the executive branch unless the Senate is willing to cooperate; and the Senate is very important in shaping the third branch of government, the judiciary.

This, to me, is really a no-brainer; giving to presidential campaigns is just a far, far worse way to spend your political money than giving to House, Senate, or state and local campaigns — if you want your money to matter.