Their choice: to obey the will of leftist party leaders like Sen. Chuck Schumer (D-N.Y.) and Rep. Nancy Pelosi (D-Calif.), or honor the will of the Trump voters they represent.
Facing tough battles for re-election in November, senators like Joe Donnelly of Indiana, Heidi Heitkamp of North Dakota, Claire McCaskill of Missouri and Joe Manchin of West Virginia are under tremendous pressure to confirm Kavanaugh to the Supreme Court, but this would hand Trump a major victory and earn them the scorn of their Democratic colleagues.
On the other hand, if they tow Schumer's line and vote Kavanaugh down, politically they risk signing their own death warrants.
According to Democratic campaign consultant Douglas Schoen, "Ultimately, this is a lose-lose situation."
"For these red state Democrats, confirming Kavanaugh could even garner them some Republican-leaning votes in their own states," Schoen writes. "There is also the possibility, though, that far-left Democrats from deep blue states would condemn those senators who vote to confirm Kavanaugh, leading to an even greater divide within the Democratic party."
He adds: "If Democrats stand firm on opposing any Trump nominee, however, they run the risk of losing seats and perhaps even the chance of regaining a majority."
In 2017, Donnelly, Heitkamp and Manchin voted to confirm Neil Gorsuch to replace Justice Antonin Scalia. But McCaskill hesitated and ultimately voted against him. Her reputation was tarred among Missouri's conservative electorate, leading to a slump in her approval rating. McCaskill's 2018 Republican opponent, Josh Hawley, has issued a political ad accusing her of plotting to fill the Supreme Court with "liberals."
Democrats opposing his nomination will not be able do so, many conservatives believe, for any reason other than pure, partisan politics.
"As a Democrat running for re-election in a solid red state," Schoen observes, "McCaskill does not have the same freedom to oppose Kavanaugh with an election only months away."
Likewise, he notes, Donnelly, Heitkamp and Manchin are fighting to convince their pro-Trump, deep-red constituencies to return them to Washington.
"It behooves these three Democrats to once again vote across the aisle for their own sake to keep their Senate seats," says Schoen. "Voting against Kavanaugh could very well give their Republican challengers the support they need to vote them out of office."
Of the four finalists to succeed Justice Anthony Kennedy, Kavanaugh is widely regarded as the "most difficult" for Democrats to scuttle.
"Brett Kavanaugh is basically John Roberts 2.0," says National Review's Dan McLaughlin. "He's not the most populist choice, or the most politically provocative. But he's a serious movement conservative, brilliant, universally well-liked, experienced, and independent-minded and a devoted critic of the administrative state."
"[H]e's also got a resume of experience and accomplishment that is virtually unassailable," McLaughlin continues. "He's got the credentials, he's got the credibility."
He adds: "Democrats opposing his nomination will not be able do so, many conservatives believe, for any reason other than pure, partisan politics. That's what, they believe, makes him a nightmare for Democrats."