Democrats are apoplectic that Senate Majority Leader Mitch McConnell (R-Ky.) will fill President Trump’s end-of-term Supreme Court vacancy after blocking President Barack Obama's, violating the standard he set just four years ago. Now, some are talking about packing the court or creating more states, including Puerto Rico and the District of Columbia, to add Democrats to the Senate. Is Congress falling into a whirlpool of vengeful politics where nothing is sacred?

Congress is not, and was rarely, a place where all traditions are sacrosanct. What may seem today like a radical and retributive cycle in which each party grabs any tool it can to defeat the other has been the long-term trajectory of both sides in Congress. For half a century, they have sought new ways to win partisan conflicts, even if it means creating rules, bending them or disregarding long-standing norms. It is a battlefield on which, for large parts of American history, raw power is all that matters.

Rule-bending has a long pedigree in legislative politics, especially in the 19th century. But the modern era of ignoring rules and norms in Congress for partisan gain dates to the late 1970s. House Democrats at the time were looking for new ways to keep their motley party unified and limit the ability of Republicans to cause mischief. Under House Speaker Thomas P. “Tip” O’Neill (Mass.), they began revising their chamber’s procedures in ways that gave them structural advantages, and they experimented with “special rules,” which set the terms under which bills could be considered — often by limiting amendments and curtailing debate time.

Frustrated by these special rules, and by other ways that Democrats made their life difficult, a faction of House Republicans led by backbencher Newt Gingrich (Ga.) decided to fight back. They began offering procedural motions and delivering provocative speeches in the hope of turning the floor into a partisan battleground. In mid-1984, Gingrich and his allies violated norms of courtesy by attacking Democrats by name when they were not present to defend themselves. O’Neill retaliated by secretly panning the House’s TV camera to show that Republicans were speaking to an empty chamber. The move backfired, however, creating a fracas that gave Gingrich national attention and encouraged others to use the floor as a partisan stage to lob verbal grenades.

Three years later, House Democrats got creative when a special rule for considering a reconciliation bill was unexpectedly defeated. They adjourned the chamber and quickly reconvened, creating a “new” legislative day, which allowed them to bring a second rule to the floor. It passed, but the bill itself was approved only after Speaker Jim Wright (Tex.) held the clock open until one reluctant Democrat switched his vote.

Republicans angrily accused Democrats of abusing their power. Yet later, when it was their turn in the majority, they doubled down. In June 2003, Speaker J. Dennis Hastert (R-Ill.) extended the voting time by more than half an hour while party leaders scoured the floor for enough votes to pass a Medicare prescription drug bill. Five months later, when the final version of the legislation returned to the chamber floor, Hastert kept the vote open for nearly three hours — a House record — until a majority of lawmakers finally voted for it.

For many years, it seemed as though the Senate might avoid the same tit-for-tat pattern of abusing rules and ignoring norms. A bipartisan group of senators known as the Gang of 14 agreed in 2005 to stop Democratic filibusters against judicial nominees in exchange for keeping the chamber’s filibuster rules in place. The agreement didn’t last. In 2013, tired of GOP filibusters of Obama’s nominees to the federal bench, Democrats invoked the “nuclear option,” approving an unusual interpretation of Senate rules that ended the power of a minority to filibuster nominations to the executive branch and lower federal courts. Republicans had opposed the nuclear option, but they changed their minds in 2017 and used it to end the filibuster for Supreme Court nominees as well.

The Senate GOP’s blocking of Merrick Garland’s nomination in 2016 may not have violated the Constitution or Senate rules, but it certainly exceeded the limits of what had been considered acceptable behavior. Not since the mid-19th century had the Senate refused even to hold hearings on a judicial nominee, let alone one as widely respected as Garland. McConnell tried to explain that it was “about a principle, not a person,” but Republicans soon abandoned their so-called principle when it was politically convenient.

Partisan rule-bending in the Senate has happened on other matters, too. Last year, Democrats upset about a controversial immigration bill refused to attend a Judiciary Committee meeting to discuss the measure. Without their attendance, according to committee rules, no further action could be taken on the measure. But Chairman Lindsey O. Graham (S.C.) and fellow Republicans on the panel voted to ignore the rule and approve the measure. “If the majority is willing to break any rule in order to report this bill today,” said Sen. Patrick J. Leahy (D-Vt.), a member of the panel, “there are no rules.”

There are many reasons for this development in congressional politics. Heightened party polarization and the rise of partisan “team play” have made it harder for lawmakers to empathize with colleagues on the other side of the aisle. Greater electoral competition has put increased pressure on each party to secure wins while they still hold power. In the Senate especially, the stakes over judicial nominations have become so high that the temptation to ignore rules and norms to fill the federal courts with like-minded judges is simply too great.

Perhaps most important, lawmakers seldom face sanctions for changing rules or breaking traditions to score partisan wins. There is no internal enforcement mechanism to keep a determined majority from bending or rewriting its chamber’s procedures, and most voters care more about victories for their party than about the norms that govern our political institutions. Some Senate Republicans point to their seat gains in 2018 as a sign that getting conservatives on the Supreme Court, no matter how it is done, will be rewarded at the ballot box.

These are powerful forces, and it’s hard to imagine that congressional parties will stop trying to win by any means available. This is why Senate Democrats’ threat to push the bounds even further should not be dismissed. Besides expanding their chamber and packing the Supreme Court, they have entertained the idea of eliminating the filibuster altogether or curtailing the court’s jurisdiction so it cannot hear certain cases. “Nothing is off the table,” warned Minority Leader Charles E. Schumer (N.Y.).

At the same time, many Democrats are hesitant to go that far. Joe Biden has been lukewarm about the court-packing scheme, and if he is elected president, his long service in the Senate may make him reluctant to throw more of the chamber’s rules and traditions out the window. Other Democratic senators, such as Joe Manchin III (W.Va.), have been hesitant to take the bold step of abolishing the filibuster. Democrats in both chambers may decide to focus on winning the November elections, which would allow them to shape policy without necessarily resorting to more radical measures.

Congress is not at the point where all rules and norms of conduct are sacrificed on the altar of partisanship. But the events of the past week are a reminder that the parties face strong incentives to do what they can to get what they want. Ultimately, it will depend on lawmakers’ restraint, backed by voters who care about fair play, to keep that desire to win at any cost from spiraling out of control.

Twitter: @mattngreen