Washington ? House and Senate candidates aren’t the only ones targeted by interest groups in this year’s campaign. While they have spent at least $185 million just since Labor Day to influence voters in close congressional races, outside money is pouring at similar rates into state elections for governors and down the ticket to city councils and even local sewage boards.

In just the past seven weeks, nonparty groups have spent at least $100 million on ads and get-out-the-vote efforts supporting or opposing specific candidates in state and local races, according to a state-by-state review by The Associated Press. The actual total is probably millions higher because there is no way to find out exactly how much was spent.

In California, mass mailings went out to voters in local sanitation district races from an arm of the American Federation of State, County and Municipal Employees in Los Angeles, District Council 36. In Iowa, the Everyday America PAC has been financing automated phone calls urging voters to remove three state Supreme Court justices and two Polk County judges for allowing gay marriage.

And in the Southwest, the Drug Policy Action Fund for New Mexico is airing a TV ad against the Republican nominee for governor, Susana Martinez, because she wants to repeal the state’s medical marijuana law.

Interest groups are seeking to influence voters’ choices in all 50 states, yet they often reveal little publicly about the money they’re spending, including the source.

Nationally, campaign finance laws are a long way from requiring full disclosure about such spending, the AP review found. Only about half the states impose some type of pre-election reporting by purchasers of special-interest political ads and then post the information for voters to find easily online. In congressional races, groups whose ads are targeting specific candidates close to elections must report the spending but do not always have to disclose their donors.

The Supreme Court made much of the air war possible in its ruling this year that corporations — and by extension unions, interest groups and individuals — can spend unlimited amounts of money airing ads saying pretty much anything they want about politicians at any time, including right up to Election Day.