Boycotting the hearing is probably the right call for them, although there are obvious downsides to that and obvious upsides to attending.

In a statement on Wednesday, Stephanie Grisham, the White House press secretary, did not give any indication about whether Mr. Trump or his lawyers intended to accept the invitation. But people familiar with the president’s legal strategy have said privately that they are deeply suspicious of taking part in a process they view as unfair to Mr. Trump.

“What is obvious to every American is that this letter comes at the end of an illegitimate sham partisan process,” Ms. Grisham said in the statement. “The president has done nothing wrong, and the Democrats know it.”…

The question of how much the president and his legal advisers decide to participate is likely to be a contentious one as his team wrangles with Democrats over Mr. Trump’s rights to present his defense to lawmakers and the public.

Why boycott? For just the reason Grisham gives — because the endless “witch hunt” rhetoric logically requires a show of contempt towards Nadler’s invitation. Even though Trump’s lawyers will be permitted to question Democratic witnesses this time, there are other procedural privileges which the White House has requested that Democrats won’t grant:

Boycotting also feels like a safe play politically given how weak the impeachment polling has been for Democrats lately. At best Schiff’s pageant resulted in no change; at worst it cost Democrats a few points in support. (Although support for impeachment has rebounded slightly in the latest FiveThirtyEight tracker, it’s worth noting.) Might as well stay away and let them continue to steer into an iceberg. Besides, the witnesses at Nadler’s hearing are less dangerous to Trump than the witnesses at Schiff’s hearing were. Schiff was speaking to eyewitnesses, the diplomats who participated in the Ukraine business to some extent and have actual evidence. Nadler’s speaking to legal experts, scholars handpicked to tell him what he wants to hear about bribery and “abuses of power” and quid pro quos and “high crimes and misdemeanors.” How many people who watched the Schiff hearings and concluded that Trump did nothing impeachable are going to be convinced otherwise because of the academic opinion of some ardent Trump-hater like Laurence Tribe?

There may even be strategic value in skipping the hearing. If Trump’s lawyers show up and ask questions, they’re bound to tip their hand in ways great or small as to how they’ll question witnesses at the Senate trial. Better to sit back, let Schiff and now Nadler tip their own hands, and prepare for the big hearing in the other chamber.

But there’s an argument for showing up too. For one thing, it’ll look weird for Republicans to have spent two months whining that the president isn’t being allowed to examine witnesses only to have Trump turn up his nose the first time Dems extend that offer. The risk of tipping one’s hand strategically is also small considering that, again, these will be legal experts at Nadler’s hearing, not factual witnesses. Questions about the origins and meaning of the “high crimes and misdemeanors” clause of the Constitution won’t tell us much about how Team Trump plans to challenge Gordon Sondland on the evidence. And there remains a chance, however small, that Nadler’s experts actually will be effective in convincing some swing voters that what Trump did with Ukraine is a big deal, maybe even bribery within the meaning of the impeachment clause. That’s not going to move impeachment polls much but it might plant a seed of suspicion in undecided minds that ends up growing into votes for the Democrats next fall. Sure would be nice to have a smart Republican lawyer in the room to challenge any damning expert testimony before it takes root among viewers.

Plus, the objection that this is all a WITCH HUNT HOAX! is well and good, but Trump’s lawyers will obviously participate in the Senate side of the witch-hunt hoaxery. If they’re not going to boycott there, they might as well get a jump on making their case by participating in Nadler’s hearing too.

Let’s be real, though. Nothing these experts say is likely to plant any seeds in anyone’s mind. Democrats who tell themselves otherwise are palpably grasping at straws, desperate for ways to convince themselves that the impeachment inquiry might not end up as a dud among Americans after all:

Rep. Madeleine Dean (D-Pa.), who sits on the Judiciary Committee, said next week’s hearing will be key to laying out details of impeachment that “unless you’re a historian or a political scientist, you might not know.”…

Rep. John Yarmuth (D-Ky.) added there is a “real possibility” the Judiciary hearings focused on articles of impeachment could move the needle by 4 or 5 percentage points.

“I think the real possibility for a significant change is when Judiciary Committee actually debate the articles of impeachment and possibly the trial,” Yarmuth said.

But, he acknowledged, “I don’t think it’ll ever get to 60 percent.”

Even if support rises four or five points, it won’t make a difference to a single vote in the Senate. It could make a difference to votes next November, as I said above, but that goes both ways. If the hearings don’t go especially well for Nadler, with the experts more equivocal than he expected — or with Trump’s lawyers showing up after all and effectively undermining their arguments — how much more might public support for impeachment decline? Nadler has no choice but to proceed but let’s not pretend his hearings are a risk-free exercise for his party.

Exit question: If you’re the political equivalent of Rocky Balboa, you have to get in the ring by sending your lawyers to fight at Nadler’s hearing, no?