The anti-abortion and anti-gun-control lobbies apparently are so powerful at the State Capitol that their mere threat to tell voters how legislators voted on a bill is enough to stop said bill in its tracks. When nonprofit groups of any ideological stripe have that much clout, voters deserve to know where they get the money they spend on politics.

But unless something gives this week in the Minnesota House, voters in 2014 won’t know who bankrolls those groups’ political messages. The National Rifle Association and Minnesota Citizens Concerned for Life thus far have blocked a House vote on a bill that would require entities, including them, to reveal their largest donors when they engage in independent election-related spending — that is, spending other than direct donations to candidates.

A push Monday from DFL Gov. Mark Dayton has not yet been sufficient to bring a stalled campaign finance disclosure bill to a vote in the DFL-controlled House. But advocates for the bill say they plan another attempt, perhaps as early as today. (The Senate’s version has cleared two committees, but it won’t advance further unless the House’s bill shows signs of life.)

As Dayton noted, the bill in question does not stifle free speech. The U.S. Supreme Court has several times affirmed that laws requiring disclosure of campaign donations pass constitutional muster. “This just says that people have a right to know where the money is coming from,” Dayton said. “These interest groups, all across the spectrum, have sources of funding that people are not aware of. People have a right to know.”

People do indeed, especially given the increasing flow of national independent expenditures into state elections. Statehouses have become battlegrounds over alternative visions of American democracy, with legislative agendas and policy templates arising from national sources on both the left and the right.

Minnesota-based affiliates of national groups are appearing, too, and are proving adept at skirting the independent expenditure disclosure requirements enacted by the 2010 Legislature in the wake of the U.S. Supreme Court’s Citizens United case. Witness a recent mailing from Americans for Prosperity Minnesota to Edina’s District 49A about its state representative, DFLer Ron Erhardt. That group is the state affiliate of Americans for Prosperity, which was founded by conservative oil magnate David Koch and refuses to disclose its donors.

The mailing says Erhardt joined Dayton and President Obama in foisting a “failed system” of health care — MNsure — on Minnesota families. But nowhere does it use the words that trigger the state’s existing disclosure requirement: “vote for” or “vote against.” Without that language, the names of those paying for the attack against Erhardt can be shielded from curious voters.

DFL Rep. Ryan Winkler’s bill would close that loophole. Any mass-delivered message that can be “reasonably interpreted to advocate the election or defeat of a candidate” would need to identify donors whose gifts exceed $5,000.

The bill also says that if any group communicates with all of the voters in a district about a candidate 30 days before the primary or 60 days before the general election, that message is “electioneering communication” subject to a donor disclosure requirement. An example of such “electioneering” would be MCCL’s practice of informing voters about incumbents’ records on bills of MCCL’s choosing shortly before an election.

Winkler’s bill would affect groups of all political stripes. But liberal-leaning groups that have engaged in the same kind of election messaging don’t oppose the measure, he said.

It’s ironic that in striving to spare themselves from disclosure requirements, MCCL, the NRA and the business groups that also oppose the disclosure bill are demonstrating why disclosure is good for democracy. Clearly, these groups’ political tactics are effective. They have substantial public policy influence at the Legislature with very little public accountability.

Understandably, they want to keep it that way. Minnesotans should not let them. Dayton said Monday, “Let’s see who’s willing to stand up and buck that kind of pressure, for something that’s clearly in the public interest.” We second his motion.