The Fix's Amber Phillips breaks down why Congress is unlikely to pass major gun control legislation, despite Sen. Chris Murphy (D-Conn.) filibustering for 15 hours on June 15. (Peter Stevenson/The Washington Post)

Senate Democrats filibustered for nearly 15 hours into early Thursday to push the Senate to respond to the horrific murders in Orlando. Led by Sen. Chris Murphy (D-Conn.), Democrats filibustered a pending bill to fund the Commerce, Justice and Science (CJS) appropriations bill. They finally announced they had won a commitment from GOP leaders to allow votes on two amendments to place new restrictions on gun purchases.

Given how rare “talking” filibusters are in the modern Senate, here are some quick thoughts on why Democrats took to the floor to filibuster an otherwise routine spending bill.

What happened?

Murphy took to the floor Wednesday morning after the chamber had just unanimously voted to take up the CJS bill. After Senate Majority Leader Mitch McConnell (R-Ky.) and Sen. Richard Shelby (R-Ala.), the chair of the Senate Appropriations Committee, submitted two amendments to the bill, Murphy was recognized to speak and launched into his filibuster.

Murphy was joined intermittently by more than three dozen fellow Democratic senators. So long as Murphy only yielded to colleagues for questions, no other senator could be recognized — thereby sustaining the filibuster and stalling Senate leaders eager to make progress on spending bills before breaking for the party conventions.

Was it really a filibuster? And what did Murphy want?

Some doubt that Murphy’s extended speech-making counted as a filibuster, arguing that a filibuster has to be aimed at blocking a bill. But senators have filibustered in the past to take bills hostage — not because they opposed the bill but because they sought action on another measure.

In this case, Murphy sought to force Republicans to allow votes on two amendments to the CJS bill: one amendment by Sen. Diane Feinstein (D-Calif.) would prevent people currently (or in the recent past) on the government’s terror watch list from purchasing guns. The other by Murphy would expand background checks for gun purchases to gun shows and online sales. A version of the Feinstein amendment failed 45-54 on a near party-line, procedural vote in December. An alternative amendment offered by Sen. John Cornyn (R-Texas) also died on a procedural vote that day, 55-44.

Why did Democrats filibuster to secure a vote?

Welcome to the Senate’s Byzantine rules and procedures. Unlike the House, the Senate lacks a simple majority rule that allows a senator to offer an amendment and gain an up or down vote on its adoption. Nor does the Senate have a rules committee like the House that the majority party can exploit to shape which amendments will come up for a vote.

Instead, to get a vote on an amendment, senators have two choices. Senators can secure the unanimous consent of their colleagues to make a vote in order, thereafter usually requiring just a simple majority vote for its adoption. Alternatively, a senator can secure the votes of sixty senators to cut off debate to (slowly) get to a vote.  (Because we’re in Byzantine territory, there’s a third option as well: senators could unanimously agree to make an amendment in order but then require sixty votes for its adoption.)

As Murphy vowed upon taking the floor on Wednesday: “I don’t think that we should proceed with debate on amendments to this bill until we have figured out a way to come together on at least two simple ideas that enjoy the support of 80 percent to 90 percent of Americans.”

Translated, Murphy sought an agreement to put the two amendments to a vote, preferably requiring just a simple majority for adoption. Because both parties would have to agree to such votes, Republicans could insist on concessions — either to the language of the proposal or to how the vote would take place.  One could imagine Republicans insisting on “side-by-side” amendments such that both Feinstein and Cornyn’s amendments would be voted on, but each would require 60 votes to be adopted. (Such a supermajority threshold might put adoption of the amendments out of reach — affording Democrats only a chance to go on record.)

But why filibuster to secure a vote? E.E. Schattschneider said it best over a half-century ago: “The most important strategy of politics is concerned with the scope of conflict.” Simply put, Democrats exploited Senate rules to expand the “scope of conflict”. In the wake of a crisis, Democrats wanted to draw a more attentive public into their fight. Democrats wagered that the visibility of a filibuster might generate some leverage in a long-running battle to impose new restrictions on gun purchases.

Of course Democrats gain politically — even if the Senate (let alone the House) does not eventually adopt the gun control amendments. Granted, conservative GOP might welcome the chance to show their loyalty to gun rights advocates by voting down the amendments. But moderate Republicans — particularly those facing voters in blue states this fall — could face conflicting pressures when a vote is called. All but one Republican voted against similar proposals last winter. Are the Orlando deaths sufficient to force moderates to side with gun control advocates?

McConnell might have wanted to avoid a potential wedge within his party over the issue, which would help account for why Democrats decided to go public with their effort to secure commitments from the GOP for floor votes.  Admittedly, GOP leaders’ silence over the course of the filibuster make it hard to know how much of a concession GOP leaders might be making in allowing floor votes. Still, issues that potentially divide a party are typically bad news for a party brand name in the run up to an election.  (Floor votes, however, are surely the least of GOP worries as it moves to nominate a new standard bearer in Cleveland in July.)

So what happened to the GOP promise for “regular order”?

Count me a skeptic of the concept of “regular order” in the Senate. Any legislative body that often requires unanimous consent to forge a way forward isn’t well described by the term “regular order.” Regardless, McConnell promised in 2015 that Republicans would restore the Senate to its old working order — emphasizing a return to debating and voting on appropriations bills and on senators’ preferred amendments. I don’t know whether Democrats had anticipated or perhaps already knew that Republicans would not allow votes on gun control amendments this week. Either way, the Murphy filibuster signals that regular order is a tough row to hoe for Republican leaders in a polarizing and electorally tense Senate.