WASHINGTON — Leading in the early polls before he’s even announced his 2020 candidacy, Joe Biden has a problem on his hands.

If he jumps in, he has to compete against a field — as well as norms and practices — that have changed since the last time he ran solo back in 2007-2008.

Consider what happened over the weekend:

A former Nevada political candidate, Lucy Flores, accused Biden of touching her shoulders, smelling her hair and kissing the back of her head, underscoring how behavior once seen as unremarkable or commonplace is now unacceptable in today’s Democratic Party. (Biden released a statement Sunday saying it wasn’t his intention to act inappropriately, as aides and friends defended the former vice president.)

Beto O’Rourke held rallies in three Texas cities in one day (El Paso, Houston and Austin), setting the early campaign pace for the 2020 field.

Bernie Sanders appeared to be on pace to raise more than $20 million for the first quarter, revealing the power of grassroots online donations in today’s politics.

Political elites continued to buzz about the 37-year old Pete Buttigieg, who this morning announced raising more than $7 million for the first quarter.

And Rep. Alexandria Ocasio-Cortez, 29, took aim at the Democratic Congressional Campaign Committee’s effort to blacklist vendors who work with candidates challenging incumbents, underscoring the progressive-versus-establishment split inside the party.

Biden’s greatest strength is the fact that he’s been in the political mainstream of the Democratic Party for the last 40 years, as one of us said on “Meet the Press” yesterday.

And that fact is also his greatest weakness.

So a death by a thousand cuts is one (likely) scenario for Biden, if he runs.

But there’s another scenario, too: His past becomes THE story for the 2020 campaign, making it difficult for other candidates to break through, a la Trump in ’16.

Of course, there’s a big difference between Biden and Trump: One can be shamed; the other one can’t.

Tweet of the day

This is just a preliminary analysis, but our team’s initial report shows we raised over $7 million dollars in Q1 of this year. We (you) are out-performing expectations at every turn. I'll have a more complete analysis later, but until then: a big thank you to all our supporters. pic.twitter.com/rDmTEiTfCs — Pete Buttigieg (@PeteButtigieg) April 1, 2019

“Wait-and-see” on Mueller investigation

The headline from our latest NBC News/Wall Street Journal poll is that the American public doesn’t see a clear verdict about whether President Trump has been cleared of wrongdoing in the Russia probe.

Twenty-nine percent of adults say they believe Trump has been cleared of wrongdoing, based on what they’ve heard about Robert Mueller’s findings.

That’s compared with 40 percent who say they don’t believe he has been cleared.

And a third of Americans — 31 percent — say they’re not sure if Trump has been cleared.

That includes nearly half of independents (45 percent), as well as a quarter of Democrats (27 percent) and Republicans (25 percent).

Bottom line: Despite all the coverage of Attorney General William Barr’s SUMMARY of Mueller’s findings, the American public still hasn’t made up its mind.

The Mulvaney Presidency

The New York Times reported over the weekend that the proposal to eliminate funding for the Special Olympics was pushed through by acting White House chief of staff Mick Mulvaney and his staff at OMB.

This combined with the renewed health-care push is a reminder that President Trump’s biggest political vulnerability is being turned into a conventional conservative whose policy ideas just aren’t popular.

2020 Vision: What we saw at Beto’s El Paso rally

One of us traveled to El Paso over the weekend to cover the first leg of Beto O’Rourke’s three-city swing through Texas on Saturday.

Here’s what we observed:

Beto doesn’t use a Teleprompter;

His campaign didn’t release speech excerpts;

His campaign excels at building picturesque rally settings (also see his last stop in Austin);

His speech covered the bases on policy (health care, education, climate change), clearly reacting to the earlier criticism that he had lacked policy specifics;

His speech had a heavy emphasis on immigration and the border battle (“Let's make sure that we never take another child from another mother after her most desperate and vulnerable moment”);

And he made unity his other big theme (“Let's agree, going forward, before we are anything else, we are Americans first”).

On the campaign trail today

Cory Booker (11:30 am ET), Julian Castro (12:07 pm ET), Amy Klobuchar (1:30 pm ET), Beto O'Rourke (2:08 pm ET), Bernie Sanders (3:00 pm ET), Elizabeth Warren (3:37 pm ET), Jay Inslee (4:50 pm ET) and Kirsten Gillibrand (5:18 pm ET) participate at the "We the People" summit in DC... Castro also speaks at the National Association of Hispanic Publications... And Kamala Harris addresses the California Union Legislative Conference in Sacramento.

Data Download: The number of the day is … 73 percent.

Seventy-three percent.

That’s the combined share of Democratic primary voters who say they’re either enthusiastic (33 percent) or comfortable (40 percent) with Joe Biden as a presidential candidate.

That makes Biden the most palatable candidate for Democrats out of the five top contenders we polled, at least at this stage. (Note: The survey was in the field March 23-27, before the Lucy Flores story. We’ll also be polling other Dem candidates in future NBC/WSJ polls.)

For Bernie Sanders, it’s a combined 62 percent enthusiastic or comfortable. For Elizabeth Warren, it’s 57 percent. For Kamala Harris, 52 percent. And for Beto O’Rourke, 48 percent.

It’s worth noting that both Harris and O’Rourke could have some significant room to grow.

Nearly one-in-five Democratic primary voters say they don’t know enough about those candidates to make a call yet.

The Lid: Money, money, money

Don’t miss the pod from Friday, which laid out our biggest questions about how 2020 candidates are faring in their first quarter of fundraising.

ICYMI: News clips you shouldn’t miss

Trump has threatened to close the border. Adviser Kellyanne Conway says that “certainly isn’t a bluff.”

The wife of former Defense Secretary Ashton Carter says a photo of Biden touching her shoulders has been taking out of context.

NBC’s own Steve Kornacki looks at the last midsize city mayor to try to run for president.

Seth Moulton says he’ll decide on a 2020 in run “in the next few weeks.”

Elizabeth Warren’s finance director is out as her campaign struggles to raise cash.

Virginia Lt. Gov. Justin Fairfax says he passed a polygraph test about allegations of sexual assault.

Other news that’s out there…

Trump agenda: Wait and see

Here’s what our NBC/WSJ poll found about public views of the Mueller findings so far.

Here’s why New York’s attorney general should make Trump nervous.

Here’s how Mitch McConnell is shutting down Nancy Pelosi’s agenda.

Is Trump facing a “red-line moment” with Putin in Venezuela?

2020: The Accused

Here’s NBC’s wrap of the Lucy Flores accusations and Biden’s response.

Here’s what John Hickenlooper had to say about the Biden charge.

The AP looks at how Kamala Harris’s calls for criminal justice reform are surprising observers of her early career.

Elizabeth Warren and Amy Klobuchar are both looking at plans to break up Big Ag.