The Senate tasked with holding President Trump’s impeachment trial would be unrecognizable to most of its predecessors.

It’s particularly true for those who ran the last trial 21 years ago, a GOP-led Senate that logged almost 1,200 hours in session. By the end of 1999, senators had cast more than 350 votes on legislation and ushered into existence 170 laws, signed by a president after they tried and failed to evict him from office. It took more than 15,000 pages to cover that year’s Senate work in the Congressional Record.

The current Senate logged almost 230 fewer hours of floor time in 2019, voting just 108 times on actual legislation. And through the first 11 months of last year, the Senate’s official footprint covered just 6,779 pages in the Congressional Record.

By almost every measure, today’s Senate is the least deliberative in the modern era of a chamber that bills itself as the world’s greatest deliberative body.

Now, this atrophying Senate has been handed the most weighty of constitutional duties, holding Trump’s impeachment trial.

Many longtime senators question whether this venerable institution has the know-how anymore to navigate such a combustible issue, the way that group in 1999 managed to reach a 50-to-50 vote on Bill Clinton’s impeachment without diminishing the chamber.

“We can bring back Phil Gramm and Ted Kennedy, but it might be a little difficult,” said Sen. Pat Roberts (R-Kan.), who was entering his third Senate year when the Clinton trial began.

Gramm (R-Tex.) retired at the end of 2002, a conservative who also cut significant bipartisan deals as chairman of the Banking Committee. Edward M. Kennedy (D-Mass.), who died in 2009, was a liberal whose closest friends included several conservative senators.

When a partisan standoff delayed the start of Clinton’s trial, Kennedy and Gramm stepped forward to forge a compromise about how it would unfold. Because of their unquestionable ideological bona fides, and because each knew how to broker deals, their pact had the gravitas to win a 100-to-0 vote.

There is no Ted Kennedy in today’s Democratic caucus, and there is no Phil Gramm in the GOP conference.

Almost everything gets left to Senate Majority Leader Mitch McConnell (R-Ky.) and Minority Leader Charles E. Schumer (D-N.Y.), two partisans whose formative years were spent running the respective campaign committees. They view almost every vote through the lens of how it will be perceived in a 30-second campaign ad.

This transformation of the Senate is not some long, slow slide over decades — no, it’s come in less than a decade.

McConnell’s predecessor, Harry M. Reid (D-Nev.), working closely with Schumer earlier this decade, undermined the power of committee chairmen, centralized power in his office and, for almost three years, bottled up any legislation that would have forced vulnerable Democrats into politically tough votes.

It didn’t work. Reid and Schumer oversaw a disastrous 2014 midterm defeat, handing McConnell the majority as he promised a new start and powerful committee chairmen leading free-flowing debate on the Senate floor.

It lasted about a year.

The result is a breathtaking transformation of how the Senate functions. An examination of data from Senate archives, some compiled by C-SPAN and others maintained by the nonprofit ProPublica, reveals:

●In 2019, just 25 percent of all votes came on legislation, easily the smallest share since at least 1989. In 2003 and 2004, the most recent similar time frame of a GOP presidency, almost 85 percent of votes pertained to actual legislation.

●The Senate spent just 257 hours in actual debate last year, less than a third of the time the chamber was in session, down by more than 150 hours from 2017.

●In 2015, McConnell’s first year as majority leader, 43 senators spoke on at least 30 days, about once a week while the Senate was in session. In 2019, just 26 senators spoke at the once-a-week rate, while 23 senators spoke fewer than 10 days over the entire year.

The arrival of Sen. Mitt Romney (R-Utah) a year ago brought great fascination, especially after the 2012 GOP presidential nominee penned a defiant Washington Post op-ed last January challenging Trump’s moral character.

Romney spoke during floor debate just seven days, for a total of 64 minutes, according to C-SPAN’s records.

“There’s just no major legislation that is taking up days of debate, which we used to see a lot,” said Robert X. Browning, a congressional scholar at Purdue University who also serves as executive director of C-SPAN’s archives.

Democrats were more blunt. “Let me tell you what: You could shoot a cannon through this chamber and not hit a bill that we’re debating,” Sen. Richard J. Durbin (D-Ill.) told reporters late last month.

McConnell defends the new Senate as one that may look different, but still churns beneath the surface. “I think most Kentuckians are proud of the fact that someone from our state is in the position I’m in. It’s not just question of pride, it’s a question of delivering,” he said at a news conference in Louisville two days before Christmas.

His office’s achievement list for 2019 is long, including a major boost in defense funding, raising the smoking age to 21, repealing health-care taxes, and a new pension plan for miners.

All of those items were approved in the final days of last year, in a frenzied rush that boosted congressional output for an otherwise stale year.

Of course, No. 1 on McConnell’s accomplishment list was “transformation of the courts,” something no senator takes more pride in. In three years, McConnell has ushered two justices onto the Supreme Court, 50 judges onto the critical appellate courts and more than 100 others onto federal district courts.

It’s a landmark achievement by any measure, particularly the appellate courts. With 20 confirmed to appellate benches in 2019, three of those circuit court districts have tilted to a majority of judges being appointed by Republican presidents.

Yet those 20 judges took up to only 40 votes to confirm, including procedural motions. More than 80 percent of votes devoted to nominees last year came on lower-level judges and sub-Cabinet posts.

The zero-sum game of devoting so much time to lower-level confirmations has left actual legislative debate languishing.

In fact, for most legislation these days, chairmen must lock everything down in advance and have a super-super-majority of support, requiring only a day’s debate and a couple votes on amendments.

It has left a power vacuum among the 98 senators not named McConnell or Schumer. Who is left to try to break the impeachment stalemate like Kennedy and Gramm did 21 years ago?

Roberts mentioned Johnny Isakson, the Georgia Republican, before realizing he had retired and was no longer available.

“I don’t know, maybe somebody will come, somebody surprising, will stand up and say, ‘Okay, come on, enough, we’re going to do it this way.’ So I hope that occurs,” he said.