First Read is your briefing from Meet the Press and the NBC Political Unit on the day's most important political stories and why they matter

WASHINGTON — After tallying the guilty pleas and indictments by special counsel Robert Mueller, as well as digesting the dueling Republican and Democratic memos from the House Intelligence Committee, here is what we know — so far — about the Russia probe:

Nineteen individuals have been charged with crimes, including President Trump’s former campaign chairman (Paul Manafort), as well as 13 Russians.

Five have pleaded guilty, including Trump’s former national security adviser (Michael Flynn), a former top Trump campaign and transition official (Rick Gates) and a former campaign adviser (George Papadopoulos).

Both Republicans (the Nunes memo) and Democrats (the Schiff memo) have confirmed that the FBI’s Russia probe originated with Papadopoulos’ claim to Australia’s top diplomat that Russia had dirt on Hillary Clinton.

The Schiff memo reveals that, by mid-September 2016, the FBI had opened “sub-inquiries” into MULTIPLE individuals connected with the Trump campaign — beyond former adviser Carter Page.

Whether or not Mueller ever finds a smoking gun that Trump and his campaign colluded with Russia, this is already the biggest political scandal in decades. And we are just more than a year into Trump’s presidency and nine months into Mueller’s probe. “Clearly the worst presidential scandal since at least Iran-Contra, but probably since Watergate,” said political scientist Jonathan Bernstein.

And this does NOT include other moving parts of the Russia inquiry, including that June 2016 Trump Tower meeting with a Kremlin-connected lawyer, Donald Trump Jr.’s direct messages with WikiLeaks, Trump constantly invoking the WikiLeaks revelations during the final month of the 2016 race, and Jared Kushner’s inability to obtain a permanent security clearance.

As the New York Times’ Peter Baker wrote over the weekend, nothing produced by Mueller’s probe has indicated wrongdoing by President Trump or illegal collaboration with Russians or Russian intermediaries. But Gates’ guilty plea on Friday is getting closer to the president.

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“The presumption in Mr. Trump’s circle is that Mr. Gates may not have any incriminating information about the president but could be a dangerous witness against Mr. Manafort, who in turn could threaten Mr. Trump,” Baker reported.

Trump's (slight) bump in the polls is over

Over the weekend, CNN and USA Today released new polls showing Trump’s job rating below 40 percent — 35 percent in CNN, 38 percent in USA Today/Suffolk. And with those polls, Trump’s average in the FiveThirtyEight tracker is below 40 percent for the first time in nearly a month.

Political pollster Charles Franklin makes an important point: Trump’s numbers in live-caller/cell phone polls (like CNN’s, Suffolk’s and NBC/WSJ’s) have been worse than in robo/no-cell polls like Rasmussen. And with Gallup’s live-caller moving from a daily to weekly tracking, Franklin adds, that means that polling averages aren’t represented as much by liver-caller polls. Instead, they’re represented more by robo polls like Rasmussen.

Toomey admits expanded background checks wouldn’t have prevented Parkland shooter

On “Meet the Press” yesterday, there was this exchange with Sen. Pat Toomey, R-Pa.:

CHUCK TODD: But there’s no part of the law that would have mandated that information make it into the background check system. How would your bill deal with that?

TOOMEY: Uh, it wouldn’t. uh you know the fact is the bill that Joe Manchin and I introduced and that we still support, Chuck it’s not going to solve all the problems and we never suggested it would. And one of the challenges we face is what to do about someone who is clearly mentally deranged, but they haven’t acted out yet in a way that allows you to adjudicate them as dangerously mentally ill or they haven’t committed a crime. Clearly in this case there were all kinds of warning signs that were advertised, right? That were communicated. And nothing was done. That’s a problem.

Still, per NBC’s Kailani Koenig, Toomey said he’s hopeful that his background-check bill could pass. "I’ve spent a lot of hours on the phone and communicating other ways with my colleagues this week," he said. "I do think there are some members who were not supportive in the past and are reconsidering. I haven't gotten anyone who said, 'Yes, sign me up,’ but there are definitely members who are reconsidering. The president’s expression of support for strengthening our background check system is very constructive.”

Klobuchar: Tech companies should face fines if they don’t get rid of “bots”

Also on “Meet” yesterday, Sen. Amy Klobuchar, D-Minn., said “she believes tech giants like Facebook and Twitter should face fines if they fail to get rid of ‘bots’ after they are discovered by the government. ‘I think that would be a great idea,’ she said when asked on Sunday’s ‘Meet The Press.’ ‘But then you need a Congress to act and there are too many people who are afraid of doing something about this because we know these sites are popular.’”

Feinstein fails to get endorsement from California Democratic Party

Turning to midterm news… “In a sharp rebuke to Sen. Dianne Feinstein, the California Democratic Party has declined to endorse the state’s own senior senator in her bid for reelection,” Politico writes. “Riven by conflict between progressive and more moderate forces at the state party’s annual convention here, delegates favored Feinstein’s progressive rival, state Senate leader Kevin de León, over Feinstein by a vote of 54 percent to 37 percent, according to results announced Sunday.”

More: “Neither candidate reached the 60 percent threshold required to receive the party endorsement for 2018. But the snubbing of Feinstein led de León to claim a victory for his struggling campaign.”

But remember, under California’s Top-2 “jungle primary” system, not getting the Dem Party’s endorsement isn’t a fatal blow, especially with Feinstein leading in the polls against the lesser-known de Leon.

Democrat Conor Lamb in PA-18 race: “I’ve already said on the front page of the newspaper that I don’t support Nancy Pelosi”

Finally, in next month’s special congressional election in PA-18, Democrat Conor Lamb has a new TV ad in which he repeats he doesn’t support Nancy Pelosi. “My opponent wants you to believe that the biggest issue in this campaign is Nancy Pelosi. It's all a big lie. I've already said on the front page of the newspaper that I don't support Nancy Pelosi.,“ he says to the camera.