Today, Obama announced three judicial nominations to the D.C. Circuit Court of Appeals, a central ideological battleground, and effectively dared Senate Republicans to filibuster his choices. “What’s happening now is unprecedented,” Obama said this morning, in a reference to ongoing GOP obstruction of his nominations. “For the good of the American people, it has to stop.”

Republicans deny that their obstructionism is unprecedented. As it happens, though, there is a set of actual facts we can look at to try to determine who is right.

If current obstructionism continues, Dems may exercise the nuclear option and change the rules by simple majority to nix filibusters of nominations. With the showdown escalating, the battle is already being treated as a he-said-she-said argument in which there’s no real way to settle the core question of whether what we’re seeing from Republicans is something new and different. For example, the New York Times noted without comment the other day: “Republicans deny being slow to confirm the president’s choices for his cabinet and the courts.”

Yes, but are they right, or wrong? It is not easy to conclusively determine whether GOP obstructionism is unprecedented. But there are some data points we can look at.

For instance, Dr. Sheldon Goldman, a professor of political science at the University of Massachusetts who focuses on judicial nominations, has developed what he calls an “Index of Obstruction and Delay” designed to measure levels of obstructionism. In research that will be released in a July article he co-authored for Judicature Journal, he has calculated that the level of obstruction of Obama circuit court nominees during the last Congress was unprecedented.

Goldman calculates his Index of Obstruction and Delay by adding together the number of unconfirmed nominations, plus the number of nominations that took more than 180 days to confirm (not including nominations towards the end of a given Congress) and dividing that by the total number of nominations. During the last Congress, Goldman calculates, the Index of Obstruction and Delay for Obama circuit court nominations was 0.9524.

“That’s the highest that’s ever been recorded,” he tells me. “In this last Congress it approached total obstruction or delay.”

By contrast, during the 108th Congress, from 2003-2004 – which is the most comparable, because George W. Bush was president and Republican controlled the Senate, meaning Dems had to use procedural tactics available to the minority to block nominations — the Index of Obstruction and Delay for Bush circuit court nominations was far lower, at 0.6176.

On Obama’s district court nominations during the 112th Congress, Goldman’s Index of Obstruction and Delay was a high 0.8716, he says. Nothing in Bush’s years comes even close, he adds.

“It is true that when Democrats controlled the Senate and Republicans were in the White House, the index has spiked, especially during Bush’s first two years,” Goldman says. “But it is unprecedented for the minority party to obstruct and delay to the level that Republicans have done to Obama in the 112th Congress.”

Meanwhile, a recent report from the non-partisan Congressional Research Service concluded:

President Obama is the only one of the five most recent Presidents for whom, during his first term, both the average and median waiting time from nomination to confirmation for circuit and district court nominees was greater than half a calendar year (i.e., more than 182 days).

And to his credit, Ron Fournier today tried to determine whether it is indeed true that GOP obstructionism is unprecedented. He wrote:

The time it takes to confirm a nominee has skyrocketed, a trend that makes the federal bench less appealing to the best and brightest. Obama made 212 nominations with an average wait of 224 days until the confirmation phase, according to data compiled in November 2012 by USA Today from the White House and the Alliance for Justice.

At the same point in their tenures, Bush had nominated 225 lawyers with an average wait of 176 days, while Clinton made 237 nominations with an average lag of 98 days. The most obvious cause of these numbers is GOP obstructionism.

None of these data points is perfect, and surely there are other ones that complicate the picture. And it remains true that the White House has, in fact, been too slow in pushing nominations. But the point is that there is a set of actual facts and data we can look at to try and determine whether Obama is right in claiming that the GOP blockading of his nominations represents something radical and different — justifying a nuclear response, if necessary — rather than continuing to allow this dispute to hover in a kind of he-said-she-said limbo.

Greg Sargent writes The Plum Line blog, a reported opinion blog with a liberal slant -- what you might call “opinionated reporting” from the left.