WASHINGTON - The August recess, as it's known in Congress, is considered so sacrosanct that only one time in the past 30 years have the House and the Senate remained in session until late August.

But that lone break from summer tradition, in 1994, continues to reverberate in today's politics, both in what gun-safety advocates are demanding and on the 2020 presidential campaign trail.

Congress stayed in session until late August 1994 to pass a landmark crime bill that included a ban on assault weapons, the Violence Against Women Act, tough sentencing guidelines for federal crimes, and an expansion of the death penalty.

In the wake of a trio of mass shootings in a seven-day span, Democrats are calling for the Senate to come back into session this month to consider legislation expanding background checks for firearms purchases that was passed earlier this year by the House. And some are calling on Speaker Nancy Pelosi, D-Calif., to pull the House back to pass more aggressive proposals such as banning assault weapons.

Pelosi, who was on an official trip this past week in Central America, has resisted those calls so far. Instead, she wants to apply political pressure to Senate Majority Leader Mitch McConnell, R-Ky., who has refused for more than five months to even consider the Democratic bill to expand background checks to include private gun sales.

McConnell has proposed a more methodical negotiation among Pelosi's House Democrats, his Senate Republicans and President Donald Trump, searching for an elusive bipartisan agreement to stem the tide of the mass shooting epidemic.

"We're going to begin these discussions over the August break," he told a Kentucky radio host Thursday, pushing off any action until after Congress returns on Sept. 9. "And when we get back, hopefully we'll be in a position to agree on things on a bipartisan basis and go forward and make a law."

The senator has been recovering from a fractured shoulder after a fall at his home.

McConnell is well versed in partisan gamesmanship on August recess. Last year he announced he was canceling the summer break to process a backlog of presidential nominees who needed to be confirmed - but his advisers made clear that he also wanted to disrupt the schedules of Senate Democrats who wanted to be home campaigning ahead of the November elections.

In reality, the Senate only convened eight days during those five weeks, with that last week devoted mostly to paying tribute to John McCain, R-Ariz., after the senator's death Aug. 25.

The House, then under GOP control, left Washington July 26 and did not return until Sept. 4.

In July 2017, when McConnell wanted Republicans to repeal the Affordable Care Act, he announced the first two weeks of August recess would be cut, giving more time to debate the controversial measure. But ACA repeal failed, and McConnell adjourned the Senate Aug. 3, a few days later than originally planned.

During Pelosi's first reign as speaker, she once called the House back after lawmakers had departed for the summer break. In August 2010, a dozen days after the House's original departure, Pelosi brought lawmakers back for an afternoon to pass a teacher funding bill, but it was not a good political day for Democrats.

Then-Rep. Charles Rangel, D-N.Y., deeply enmeshed in an ethics investigation, used that rare mid-August session to deliver a stemwinder from the House floor, declaring his innocence, refusing to resign and daring lawmakers to "take your best shot" at trying to expel him.

The House adjourned later that day and did not hold another roll call until Sept. 14.

In the 19th and first half of the 20th centuries, Congress regularly adjourned during Washington's brutally hot and humid summers.

The advent of air conditioning turned Congress into a year-round job. In 1963, the Senate never took a break longer than a three-day weekend, according to the Senate Historical Office.

Back then, Sen. Margaret Chase Smith, R-Maine, actually pushed to recess all of August and September. She said legislating then only brought "confused thinking, harmful emotions, destructive tempers, unsound and unwise legislation, and ill health."

Overwhelmed by the schedule and feeling out of touch with constituents, Congress passed in 1970 the Legislative Reorganization Act, which actually mandated a roughly 30-day break from the first Friday in August until just after Labor Day.

Ever since both the House and Senate have stuck to some version of that schedule. Summers falling during presidential nominating conventions regularly serve as the longest breaks. In 2016, Congress left Washington on July 14 and did not return until Sept. 6.

The long, hot August of 1994 is the outlier in the past three decades, and it's the example that pro-gun-control lawmakers wish they could replicate this month.

Congress took a two-week break over the Independence Day holiday that summer, amid the Democratic push to pass the Clinton administration's health-care proposal and the crime bill.

Rather than leaving in late July, Democratic leaders kept the House and the Senate in session for six straight weeks of ups and downs, starts and stops. The health-care talks faded into a debate over whether to pass a smaller-scale bill, while House and Senate negotiators ironed out the differences between their competing crime bills.

A first compromise version failed in the House on Aug. 11, leading to concessions for Rangel and key members of the Congressional Black Caucus. On Aug. 21 at 8 p.m., the House passed the crime bill with a bipartisan coalition of 188 Democrats and 46 Republicans.

The suspense lasted another four days as the Senate - which approved the original crime bill with 95 votes - fought over the final draft. Republican support cratered but at nearly 10:30 p.m. on Aug. 25, 54 Democrats and seven Republicans pushed the legislation to President Bill Clinton's desk for his signature.

Lawmakers then took a two-week break, nothing like the traditional recess. Democrats won that gun debate but lost the midterms, as the GOP swept to power in both chambers.

Now, 25 years later, the issue is back front and center.

Liberals want to reinstate the assault weapons ban, which expired in 2004, and Joe Biden, the main author of the bill, faces criticism of the punitive sentencing guidelines in his drive to win the 2020 Democratic presidential nomination.

And there's the push to abandon recess, just like in August 1994.

"No hearings. No debates. No votes. Nothing," Rep. Jim McGovern, D-Mass., said in Saturday's weekly Democratic address. "Mitch McConnell ought to call the Senate back into session right now."