By the end of this week, the Senate probably will get rid of the filibuster for Supreme Court nominees, ending a procedural tool that has been available to the minority party for about 250 years and helped define the Senate as a slower, more methodical chamber than the majority-rule House.

Republicans will pull the trigger to get Judge Neil Gorsuch on the Supreme Court over a Democratic filibuster. But they say this is just the inevitable, regrettable conclusion of a war Democrats started years ago.

No surprise; Democrats argue the exact opposite: It's Republicans' obstruction over the past decade that led to this moment.

Who's right? The answer depends on your politics, which probably says more about how partisan the nation has become — and as a result, rules governing political institutions are eroding — than it does answer the question about who's to blame for the filibuster.

But because both sides are pretty convinced that the other is to blame, let's try to answer that question. Here's a guide on how to best argue who's to blame for getting rid of the filibuster.

If you think Democrats are to blame, say:

1. Democrats sent the Senate down this road in 2013, when they got rid of filibusters for all nominees except those to the Supreme Court.

“I guarantee you, it is a decision that, if they actually go through with it, they will live to regret,” warned then-Senate Minority Leader Mitch McConnell (R-Ky.). He added: "Let me assure you: This Pandora’s box, once opened, will be utilized again and again by future majorities — and it will make the meaningful consensus-building that has served our nation so well a relic of the past.”

2. Actually, it goes further back than that — to when Democrats filibustered a qualified judge in 2001

Republicans point to the battle over President George W. Bush's nomination of lawyer Miguel Estrada in 2001 to the D.C. Court of Appeals as the moment that really started the war of the filibuster. The American Bar Association unanimously rated Estrada as “well qualified” even though he had no experience as a judge. Democrats filibustered on Estrada's lack of credentials, but underlying it, Republicans believe, was Democrats' political motivation to keep Estrada off the second-highest court in the land and, potentially, off the Supreme Court. He was never confirmed.

With that, a playbook was created: If you're in the minority in the Senate, blocking or threatening to block a judicial nominee is an effective tool to gain political victories.

"It became almost routine for our Democratic colleagues to filibuster President Bush's nominees," Sen. John Cornyn (R-Texas), now the Senate's No. 2 Republican, said in a speech Tuesday.

In 2005, Senate Majority Leader Bill Frist (R-Tenn.) was so frustrated by Democratic filibusters that he made the first high-profile threat to get rid of it. Both parties worked to avoid such a fate. But the first hole was punched in the can of worms.

3. This 60-vote threshold Democrats are claiming Supreme Court justices must hit? Nonsense.

One of the Democrats' most common explanations for why they're filibustering Gorsuch has been rated by fact checkers here at The Washington Post as a misleading statement: that nominees must get 60 votes to be approved. It's true that the past six justices have received 60 votes, but there's no rule that they have to.

In filibustering Gorsuch, Democrats are putting him through a rare extra hurdle for Supreme Court confirmation votes, one that requires the Senate to find 60 senators to vote to end debate.

Two of the most controversial Supreme Court nominees in history — Clarence Thomas and Robert Bork — never had to clear such a hurdle.

For these reasons, Republicans say Democrats are forcing them to throw out the filibuster.

“We have no alternative,” Sen. Orrin G. Hatch (Utah), a senior Senate Republican, said Monday.

If you think Republicans are to blame, say:

1. You wanna talk filibusters. Let's talk about the Obama years.

That's when Senate Republicans, in the minority for six of President Barack Obama's eight years in the White House, blocked at least a dozen* of Obama-nominated judges and even Cabinet appointments — including Chuck Hagel for defense secretary, the first filibuster of any nominee to lead the Defense Department.

Lower-court benches were left virtually empty as a result, said Democratic aides working in the Senate at that time.

Senate Republicans' filibuster of three not particularly partisan District Court judges in 2013 was the last straw for then-Senate Majority Leader Harry M. Reid (D-Nev.), who pulled the trigger other majority leaders had only contemplated pulling.

In an afternoon, Democrats in the Senate voted to lower the vote threshold for all of a president's political and lower-court nominees, so that a simple majority (usually 51 votes) could get them through.

A regrettable change to centuries of Senate procedure? Maybe. But Democrats said they had no choice.

“These nominees deserve at least an up-or-down vote,” Reid said at the time. “But Republican filibusters deny them a fair vote and deny the president his team.”

*Correction: We originally incorrectly overstated how many of President Obama's nominees Republicans filibustered during this period. At the time Reid changed the filibuster, Republicans maintained they had confirmed 99 percent of Obama's judicial selections, and The Washington Post's Fact Checker counted 12 Obama nominees who did not receive a final vote/had their nominations withdrawn as a result, compared to 14 during the Bush presidency. Democratic aides working in the Senate during this time maintain that dozens more of Obama's were blocked by threats of filibusters or cloture motions filed to delay proceedings. 

2. It's Republicans who are actually pulling the trigger on getting rid of the filibuster for Supreme Court nominees, not Democrats.

Therefore, the blame rests on Republicans. Case closed.

As Sen. Mazie Hirono (D-Hawaii) said in a recent interview with NPR's Robert Siegel: “Nobody is forcing McConnell to go that route. But he is a very determined person, and he wants what he wants.”

3. Also, there's a guy called Merrick Garland who never got a vote. 

Democrats say Republicans put them in a no-win situation in February 2016, when, hours after Justice Antonin Scalia died, McConnell vowed that Republicans would not even consider President Barack Obama's pick for the seat, no matter whom he picked.

Obama's pick, federal Judge Merrick Garland, was largely considered a moderate one aimed at appeasing Republicans. But under McConnell, Republicans held the line and didn't even have a hearing for Garland, who now holds the longest wait time for any Supreme Court nominee.

“This is a stolen seat,” Sen. Jeff Merkley (D-Ore.) said in January, as President Trump nominated Gorsuch. “This is the first time in American history that one party has blockaded a nominee for almost a year to deliver a seat to a president of their own party. If this tactic is rewarded rather than resisted, it will set a dangerous new precedent in American governance.”

If you're not sure which party to blame, just say this:

There's blame to go around on both sides.

In fact, you could make the case that no matter which party started it, the demise of the filibuster was inevitable:

  • Democrats catch Republicans off guard by filibustering a Bush nominee.
  • Republicans filibuster a dozen of Obama's judicial nominees. (Democrats argue they unofficially blocked much more than that, but the definition of "blocked" is in the eye of the beholder.)
  • Democrats decide to get rid of the filibuster for all non-Supreme Court nominees.
  • Republicans hold a Supreme Court seat open for more than a year.
  • Democrats are now leading a rare filibuster of a Supreme Court nominee.
  • In turn, Republicans will probably get rid of that last shred of the filibuster for nominees.