A Democratic super PAC quietly meddled in Arizona's GOP primary too

That super PAC, blandly titled "Red and Gold," was able to conceal its donors -- and thus its links to national Democrats -- and avoid disclosure until after the election with a tactic increasingly used by other Democratic super PACs this cycle.

Last May, a pair of Democratic super PACs meddled anonymously in the West Virginia Republican Senate primary using the same arrangement.

In Arizona, like in West Virginia, the super PAC avoided disclosure by forming on August 1, within a month of the August 30 primary, and electing to file monthly FEC reports. Per FEC requirements, that meant the group wouldn't file a report detailing its fundraising and spending until September 20, nearly a month after the contest took place.

By forming shortly before the contest, getting a rush of contributions from other PACs and donors, and bombarding voters with ads over the final month, the Democratic groups played a significant, and anonymous, role in the election even over a short period of time.

In both cases, the Republican establishment's preferred candidate -- Rep. Martha McSally in Arizona and Attorney General Patrick Morrisey in West Virginia -- ultimately won their primaries against competitive conservative challengers seen by Democrats as more favorable general election matchups in key races. But even though Democrats didn't swing the nominations in either state, they were still able to anonymously bloody the leading Republican in each race.

According to Red and Gold's August FEC report, the group received nearly $3 million total in just a month from another leading Democratic super PAC, Senate Majority PAC, and from liberal megadonors like George Soros and James Simons. Senate Majority PAC has itself has received significant contributions this cycle from Simons and other major liberal donors like Donald Sussman, Fred Eychaner and Reid Hoffman, totaling more than $95 million since the beginning of 2017.

But none of that information was available to voters participating in Arizona's Republican Senate primary until just this past weekend, when the FEC reports for August were published.

Campaign finance experts had expressed concern that the tactics seen in West Virginia in May could spread to other races.

"With these kind of campaign finance shenanigans, once the dam breaks, you can expect to see a flood of similar conduct," said Brendan Fischer of the nonpartisan, nonprofit Campaign Legal Center, in May. "Once one political operative figures out how to get around the law, you see others following suit."

And that's exactly what happened in Arizona. The tactic has roots as far back as the Alabama special election in late 2017 between Doug Jones and Roy Moore, when a Democratic super PAC called Highway 31 was able to avoid revealing its donors until after the results were in by claiming to have done all their spending on credit. They disclosed their donations -- ostensibly made to pay off that debt -- after the election.