The remarks – which echo arguments Ornstein and Mann published earlier this year in their book "It's Even Worse Than It Looks" – arrived as lawmakers are ramping up the partisan debate over how to approach looming, end-of-the-year deadlines on a whole host of thorny tax and spending issues.

Those policy changes – collectively deemed the "fiscal cliff" – include expiration of the Bush-era tax rates, a sharp reduction in Medicare payments to doctors, the end of the payroll tax cut for all workers and steep cuts to defense and domestic spending that Congress approved as part of last year's sequester arrangement.

A long list of economists, including Federal Reserve Chairman Ben Bernanke, have warned that allowing those fiscal changes to take effect next year could send the country back into recession.

Congress has been unable to reach agreements on how to avoid the cliff, and Democrats used Ornstein and Mann to argue Republicans are to blame.

Republicans have been quick to blame President Obama and the Democrats for the sequester cuts. They say the Democrats haven't taken those cuts seriously, instead holding the threatened programs "hostage" to the Democrats' proposal to hike taxes on the wealthiest Americans in January.

"This administration has failed to respond to our repeated requests to come to the table to see if we can resolve this so that the sequester doesn’t hit," House Majority Leader Eric CantorEric Ivan CantorEric Cantor: Moore ‘deserves to lose’ If we want to make immigration great again, let's make it bipartisan Top Lobbyists 2017: Hired Guns MORE (R-Va.) told reporters Wednesday.

The sequester was included in August's debt-ceiling agreement, the Budget Control Act (BCA), as an enticement for the fiscal supercommittee – a 12-member bipartisan panel also created by that law – to forge an alternative deficit reduction strategy.

When the supercommittee failed in that effort, they triggered the sequestration mechanism, which will cut $1.2 trillion to defense and domestic programs over 10 years unless Congress acts first.

Democrats have pushed back against the GOP criticisms, noting that Republican leaders also voted in favor of the BCA.

"The Budget Control Act was strong medicine, but it was bipartisan," Rep. Xavier BecerraXavier BecerraOvernight Regulation: Net neutrality supporters predict tough court battle | Watchdog to investigate EPA chief's meeting with industry group | Ex-Volkswagen exec gets 7 years for emissions cheating California AG on Trump EPA: ‘It’s almost as if they believe they’re above the law’ Sanctuary city policies are ruining California — here’s why I left MORE (Calif.), vice chairman of the House Democratic Caucus and a member of the supercommittee, told reporters Wednesday. Congress, he added, has devolved into "a partisan workshop."

Rep. John Larson (Conn.), chairman of the House Democratic Caucus, hammered GOP leaders for creating "an artificial issue" by opposing a clean debt-ceiling hike – opposition that eventually led lawmakers to attach the supercommittee and sequestration provisions to avoid a government default.

"There are consequences to be paid [for opposing a clean bill]," Larson said.

Ornstein on Wednesday said the failure of the supercommittee to reach a deal was foreshadowed by Senate Minority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellGOP strategist donates to Alabama Democrat McConnell names Senate GOP tax conferees Brent Budowsky: A plea to Alabama voters MORE's picks for the panel. If McConnell (R-Ky.) had chosen just one GOP member of the so-called Gang of Six – which included Sens. Tom CoburnThomas (Tom) Allen CoburnFormer GOP senator: Trump has a personality disorder Lobbying World -trillion debt puts US fiscal house on very shaky ground MORE (Okla.), Mike CrapoMichael (Mike) Dean CrapoOvernight Regulation: Feds push to clarify regs on bump stocks | Interior wants Trump to shrink two more monuments | Navajo Nation sues over monument rollback | FCC won't delay net neutrality vote | Senate panel approves bill easing Dodd-Frank rules Overnight Finance: GOP delays work on funding bill amid conservative demands | Senate panel approves Fed nominee Powell | Dodd-Frank rollback advances | WH disputes report Mueller subpoenaed Trump bank records Senate panel moves forward with bill to roll back Dodd-Frank MORE (Idaho) or Saxby ChamblissClarence (Saxby) Saxby ChamblissLobbying World Former GOP senator: Let Dems engage on healthcare bill OPINION: Left-wing politics will be the demise of the Democratic Party MORE (Ga.) – then "we've got a deal," he said.

"And he didn't – [he] studiously avoided them," Ornstein said, suggesting McConnell didn't want to reach a deal that would give Obama a huge political victory. "These guys are not moderates, or liberals. They're strong conservatives. But they wanted to solve the problem and recognized … that revenues have to be a component of it."

Mann noted another obstacle facing lawmakers hoping to avoid the fiscal cliff: Grover Norquist's anti-tax pledge, which most Republicans have signed, takes most new revenues off the table.

"The Republicans remain too dug in to their 'no-new-tax' pledge," Mann said. "That is the major obstacle" to a deal.

Even as Ornstein and Mann were teeing off on Republicans on the House side of the Capitol, McConnell was taking a few shots at the two political scientists from the Senate chamber. In a lengthy sparring match with Senate Majority Leader Harry ReidHarry ReidBill O'Reilly: Politics helped kill Kate Steinle, Zarate just pulled the trigger Tax reform is nightmare Déjà vu for Puerto Rico Ex-Obama and Reid staffers: McConnell would pretend to be busy to avoid meeting with Obama MORE (D-Nev.) over McConnell's habitual use of the filibuster, the Kentucky Republican accused Ornstein and Mann of siding with the Democrats for ideological reasons.

"I actually know Norm Ornstein and Tom Mann," McConnell said. "They are ultra, ultra liberals. Their problem with the Senate is Democrats don't have 60 votes anymore."

Ornstein countered that there’s a difference between the two parties.

"There are no angels here. We're not saying we've got one terrific party and one awful party, and voters should throw out the awful ones and bring in the good ones," Ornstein said. "But there's a real difference now between the parties."