has been petering out for some time now as it becomes more and more obvious that the White House was not involved with targeting conservative groups for scrutiny. I don't think anyone over at Fox got that memo though. And as Steve Benen noted below, the Republicans sure haven't gotten it.

This latest revelation that the IRS singled out progressive groups ought to be putting an end to this story, but I'm not holding my breath that facts will matter to them any time soon: A 'nail in the coffin' of the IRS 'scandal':

Remember when the IRS story looked, way back in May, like a legitimate political controversy? With every passing revelation, the misguided uproar looks a little sillier.

The ranking Democrat on the tax-writing House Ways and Means Committee ranking member, Sander Levin, D-Mich., released new information Tuesday from the Internal Revenue Service to provide further evidence that progressive groups were singled out for scrutiny as were conservative groups.

The documents include an IRS training presentation that instructs IRS employees to screen tax-exemption applications for Democratic leaning "Emerge" organizations alongside "progressive" and "tea party" organizations.

Three organizations tied to the national Emerge America organization -- Emerge Nevada, Emerge Maine and Emerge Massachusetts -- sought tax-exempt status in 2011. They were denied -- the group, which helps recruit and train Democratic women for electoral politics, was deemed too political.

And so, when it came time for the IRS to scrutinize organizations, it instructed IRS employees to screen for "Emerge" along with "progressive." If the tax agency were singling out conservatives, as Republicans and a few too many reporters claimed, this obviously wouldn't have happened.

Making matters slightly more amusing, the same new materials show the IRS had a "Be On the Look Out" warning that called for heightened scrutiny to "ACORN successor" organizations.

Levin said in a statement, "Once again it is clear that the Inspector General's report left out critical information that skewed the audit's findings and set the stage for Republicans to make completely baseless accusations in an effort to tarnish the White House. These new documents make it clear the IRS scrutiny of the political activity of 501(c)(4) organizations covered a broad spectrum of political ideology and was not politically motivated. Republicans should stop trying to twist the facts to fit a faulty 'enemies list' narrative and instead join in the effort to fix the mismanagement problems at the IRS tax-exempt division as I have called for since day one."

Government Reform Committee Ranking Member Elijah Cummings (D-Md.) added, "This new information should put a nail in the coffin of the Republican claims that the IRS's actions were politically motivated or were targeted at only one side of the political spectrum."

And yet, even now, the right continues to insist there's an IRS "scandal" that only conservatives can see.

Just last week, Sen. Rob Portman (R-Ohio) had a lengthy op-ed in the Cleveland Plain Dealer, arguing that that administration needs to "come clean" on this terrible "scandal" and "cover-up." I was tempted to write a post fact-checking the whole thing, but (1) the entire op-ed was one long falsehood intended to exploit public ignorance; (2) I find it hard to believe Portman or the staffer who wrote the piece actually believes what it says; and (3) the op-ed had no real impact because it's suddenly dawning on the mainstream that there is no "scandal."

What was annoying has since become tiresome. Republicans were so heavily invested in this controversy that they feel the need to keep up appearances, but it seems they're just going through the motions -- no one could honestly take the story seriously anymore.

As Steve also wrote, no one's been held accountable for drumming up this story on every side of the aisle (and that would include a few on the network he works for as well) and there has been very little introspection among those who were telling us how serious this "scandal" was supposed to be. Sadly these days, that's the rule and not the exception.