Officials in both parties tell me that — barring surprise new information — President Trump is on a glide path to swift acquittal at his Senate impeachment trial, despite a blizzard of evidence bolstering Democrats' accusations.

• Why it matters: Trump has a decent chance of avoiding witnesses and of losing zero Republican votes on conviction.

• Think about that: When the news broke, did anyone think every single Republican in the House and Senate would have his back? Bill Clinton pined for such unity. 

A source close to House Democrats sounded morose after Trump's defense team made its opening arguments yesterday: "I think our team feels like we did everything possible and are going to lose anyway."

• "It feels like maybe we’ll still get a witness, but more likely not, and even if we do it won’t matter," the source added.
• "The GOP gamble is always that most voters don’t care about process ... Up to us to make them pay for this."

Don't rule out the possibility that the necessary four Senate Republicans will vote to allow witnesses.

• But the Trump team seems confident they won’t.

Senate sources say that about the only way the Trump team could mess things up now is to be overly shrill and overplay their hands when they continue their case on Monday,.

• The biggest way the Trump lawyers could do that is by delving deeply into the Bidens' role in Ukraine.
• People in both parties echoed an observation of CNN legal analyst Jeffrey Toobin during yesterday's coverage: "If you're winning, shut up. That's, I think, ... the guiding principle of what they're doing."
• Yesterday's presentation was also short because Trump didn’t want his lawyers wasting time on Saturday, which he tweeted "is called Death Valley in T.V."

Online interest in the first three days of the Senate impeachment trial was barely half as strong as the first three days of House impeachment hearings, according to NewsWhip data provided exclusively to Axios' Neal Rothschild.

• Why it matters: By blocking Democratic attempts to subpoena new documents, the Republican-controlled Senate made sure no dramatic new information surfaced during the first few days of the trial — and made it easier for Americans to tune out.

By the numbers: Stories about impeachment during the first three days of House impeachment hearings resulted in 32.5 million interactions (likes, comments, shares) on social media, per NewsWhip.

• There were 17.8 million interactions on impeachment stories during the Tuesday, Wednesday and Thursday of the Senate trial.
• Of the 25 stories about Trump with the most online action during those three days, only three were related to impeachment.

The bottom line: In these days of fragmentation and distraction, even the gravest constitutional process hasn't been enough to keep the country hooked.

• Share this graphic.

On opening day of the defense case, President Trump's legal team didn't try to burn down the house by going after the Bidens, Axios managing editor David Nather reports from the Senate chamber.

• Instead, the team put on a fairly conventional legal rebuttal — trying to poke holes in the House impeachment managers' case, and arguing that Democrats just don't have enough evidence of wrongdoing to throw Trump out of office — especially in a year when he's up for re-election.
• "They have the burden of proof, and they have not come close to meeting it," White House counsel Pat Cipollone said.

In the chamber: 

• Sen. Collins, Murkowski and Gardner were the most diligent notetakers of the Senate Republicans who are being eyed as possible votes to call witnesses.
• Sen. Mitt Romney, sitting at the back of the chamber, and Sen. Lamar Alexander mostly sat back and listened.
• Republicans mostly paid close attention to most of the presentations, though a few began looking away or reading as White House deputy counsel Patrick Philbin spoke. Democrats looked more bored.
• Senate Democratic Leader Chuck Schumer listened closely, scowling.

2020 watch:

• Sen. Bernie Sanders sat slumped back in his seat, fidgeting or resting with his chin in his hand (though he leaned forward with a puzzled look when Philbin criticized Schiff).
• Sen. Elizabeth Warren spent a long time hunched over a legal pad, writing and not appearing to pay close attention — though she sat up and listened to Cipollone's closing remarks.
• Sen. Amy Klobuchar took some notes and listened to some of the arguments, but often looked away and stared around the room.

What to watch: Whether the Trump team stays focused on the legal issues or veers into attacks on the Bidens when they resume arguments Monday at 1 p.m.

• Either way, Cipollone said the team doesn't plan to take the full 24 hours — because they don't think they need it.

Here are two graphics White House counsel Pat Cipollone displayed during his opening yesterday:

Ahead of the Iowa caucuses 8 days from now, the N.Y. Times says Sen. Bernie Sanders is "consolidating support from liberals and benefiting from divisions among more moderate" candidates, per the Times/Siena College poll:

• Sanders: 25%
• Buttigieg: 18%
• Biden: 17%
• Warren: 15%
• Klobuchar: 8%
• Steyer: 3%
• Yang: 3%
• Complete results (subscription).

Des Moines Register endorsement: "Elizabeth Warren will push an unequal America in the right direction."

"Fox News Sunday" anchor Chris Wallace — who has covered the Iowa caucuses since 1980 — is back in Des Moines, and talked to me ahead of a town hall he's moderating with Pete Buttigieg tonight at 7 ET.

• I asked Wallace about Buttigieg's secret sauce: "Buttigieg is young, smart as the dickens, and a fresh face on the national scene when folks are pretty tired of politics as usual. But are they willing to push the envelope this far — 38, medium-town mayor, openly gay?"

• And I asked Wallace how impeachment is playing in the Hawkeye State: "Voters are asking what the mayor thinks about impeachment. So we will reflect that in the town hall. But I don’t get the sense anyone thinks the president is actually going to be removed. So it just factors into how folks think about Trump."

Buttigieg senior adviser Lis Smith told me why the mayor is going on Fox News: "We know we can't win the primary or general by just talking to the same people over and over again."

• "Our campaign is also about elevating qualities like respect, decency, and thoughtfulness in the political discourse," Smith continued. "Those are definitely qualities that Chris embodies ... He's a tough questioner, but he's fair and has established a massive platform for himself."

P.S. A reporting tip from Chris Wallace ... Instead of just interviewing aides when he's doing background reporting, he tries to talk to the Cabinet members and lawmakers themselves: "Often they don't know what's out there, or don't know the talking points, and they tell you more!"

Ahead of tonight's Grammy Awards, Sean "Diddy" Combs called out the show for dissing rap and R&B stars, in a blazing speech that got a standing ovation from Beyoncé, Jay-Z and others, AP Music Writer Mesfin Fekadu reports.

• At the end of his 50-minute speech last night at Clive Davis' white-hot pre-Grammys gala, Combs said: "So I say this with love to the Grammys, because you really need to know this: Every year, y'all be killing us, man."

• "Truth be told, hip-hop has never been respected by the Grammys. Black music has never been respected by the Grammys to the point that it should be."

The context: Over the years, the awards show has been criticized when Beyoncé, Kanye West, Eminem, Mariah Carey and others lose in major categories.

• The rap and R&B stars often fall short of their pop, rock and country counterparts.
• And the voting process was called into question last week after the academy's just-ousted CEO, Deborah Dugan, claimed that the awards are rigged and filled with conflicts of interest.

Synthetic frogs are challenging the science-class rite of passage, as school labs turn to reusable models that feel like the real thing, The Wall Street Journal's Tawnell D. Hobbs reports (subscription):

• "A synthetic frog has leapt into the hearts of some educators and animal-rights activists. The model, complete with man-made internal organs, has become the humane answer to classroom dissections and an antidote for squeamish students."

Why it matters, from The Journal: "[S]ome teachers ask: Are we protecting students too much from the messiness of real life and real science?"

• "They say students are missing out on the feel and, yes, smell of dissecting a formaldehyde-drenched frog."
• "And gone are any surprises ... that come with a real specimen — extra limbs and organs, or bellies full of insects, rocks and even remnants of other amphibians.