Kudos to Arizona’s Sen. John McCain for stepping up to co-sponsor the Honest Ads Act, which would force Facebook, Google and other online companies to play by the same rules as older media, and disclose who’s paying for political advertising.

The bill’s Democratic sponsors, Sens. Amy Klobuchar (Minn.) and Mark Warner (Va.), are motivated by fury in their party over Russian meddling in an election that Hillary Clinton lost. But in reality, this is about far more than stopping foreign interference in US politics.

Back when today’s disclosure rules were written in 2002, Internet ads weren’t a factor. Now they are: Indeed, Trump campaign guru Kellyanne Conway cites the Clinton team’s ineptness with them as a key to the outcome.

More than $1 billion-with-a-b went for digital political ads last year, and the figure is sure to soar in the future. It would be insane not to demand transparency going forward.

Online firms may claim it’s particularly hard for them to enforce or execute disclosure — but that’s their problem. They reap endless benefits from their no questions asked as long as you’ve got the cash approach; too bad if it doesn’t serve them well here.

Facebook has actually claimed that figuring out whether an ad is commercial or political is just too challenging. Write some algorithms, folks. Or hire some more live bodies if the robots just can’t hack it.

Big Tech knows it can’t continue to fly under the radar here — but its lobbyists are at work looking to minimize the impact of new laws. Ironically, one top fixer is Marc Elias, a senior adviser to the Hillary campaign, who for years has been helping Google and Facebook request exemptions from Federal Election Commission rules.

In addition to the Senate bill, the FEC is taking a fresh look at how its regulations apply to Internet ads. It plainly needs to move past its 2006 ruling that these involve “a unique and evolving mode of mass communication and political speech that is distinct from other media in a manner that warrants a restrained regulatory approach.”

But Congress should act, too — and other Republicans should join McCain in insisting on it. This is too important to let the tech lobbyists score continued special treatment.