WASHINGTON — Notice a common number — or thereabouts — in the latest national NBC News/Wall Street Journal poll?

Trump’s percentage against Joe Biden in a hypothetical matchup: 42 percent.

His percentage against Bernie Sanders: 43 percent.

His percentage against Elizabeth Warren: 43 percent.

His percentage against Kamala Harris: 44 percent.

His job-approval rating: 45 percent.

And just to expand on this exercise, Trump’s job rating exactly a year ago in the NBC/WSJ poll was — you guessed it — 45 percent.

Ditto his job rating in the exit poll for the 2018 midterms.

It’s a reminder of how constant Trump’s numbers are, despite the always-changing news cycle … how similar Trump’s ballot numbers are to his job rating … and how perilous his political standing is given the overall state of the U.S. economy.

Incumbent presidents, especially those not facing a real primary challenge, have a baked-in advantage getting to focus on a general election for four years, instead of the four to five months the opposition gets.

And as we saw in 2016, a person can still win the electoral college by getting just 46 percent of the popular vote.

But don’t lose sight of just how unpopular the president of the United States is — and has been.

Ugly tweets

And if you’re wondering why the president of the United States remains unpopular — given the humming economy — look no farther than his tweets over the last 24 hours.

On Sunday morning, he fired off a vicious and racist tweetstorm apparently aimed at Reps. Alexandria Ocasio-Cortez, Rashida Talib, Ilhan Omar and Ayanna Pressley, saying they should “go back and help fix the totally broken and crime infested places from which they came.”

All four congresswomen are U.S. citizens and all but one (Omar being the exception) was born in the United States.

And this morning, Trump doubled-down on his attack.

But you also want to know why close to 90 percent of Republicans approve of Trump’s job, the only sitting GOP member of Congress whom we saw take issue with Trump’s tweet was Rep. Chip Roy, R-Texas, who still called for the defeat of those Dem congresswomen.

“POTUS was wrong to say any American citizen, whether in Congress or not, has any ‘home’ besides the U.S. But I just as strongly believe non-citizens who abuse our immigration laws should be sent home immediately, & Reps who refuse to defend America should be sent home 11/2020.”

Is Ross going to be tossed?

It sure looks like Commerce Secretary Wilbur Ross is being set up as the fall guy for Trump’s census defeat/retreat from last week.

“President Donald Trump has told aides and allies that he is considering removing Commerce Secretary Wilbur Ross after a stinging Supreme Court defeat on adding a citizenship question to the census, according to multiple people familiar with the conversations,” Hans Nichols, Kayla Tausche and Hallie Jackson write.

“Ross is one of the original members of a Cabinet that has seen historically high turnover, but his exit would mark the first departure of an agency head that Trump knew well before entering politics.”

“Trump and Ross met — and bonded — through Trump's Atlantic City casino hotel bankruptcies in the 1990s, with Ross representing some of Trump's creditors.”

2020 Vision: Biden takes aim at Medicare for All

NBC’s Marianna Sotomayor reports that the Biden campaign today is releasing its plan to build on and protect the Affordable Care Act, or Obamacare.

And here’s Biden in a campaign video: “I understand the appeal for Medicare for All. But folks supporting it should be clear: that it means getting rid of Obamacare. And I’m not for that.”

More Biden: “I know how hard it was to get that passed. I watched it. Starting over makes no sense to me at all.”

And: “I knew the Republicans would do everything in their power to repeal Obamacare. They still are. But I’m surprised that so many Democrats are running on getting rid of it.”

Don’t be surprised if we get a response from Bernie Sanders at his rally with unions and hospital workers in Philadelphia at 2:00 pm ET.

Sanders also is planning a big Medicare for All speech on Wednesday.

By the way, our NBC/WSJ poll tested whether voters favored or opposed “a single-payer health-care system in which all Americans would get their health insurance from one government plan that is financed in part by taxes.”

All voters who favor it: 44 percent.

All voters who oppose it: 49 percent.

On the campaign trail

Joe Biden, Cory Booker, John Hickenlooper and Amy Klobuchar speak at an AARP/Des Moines Register forum in Des Moines, Iowa… Julian Castro, Michael Bennet and Kirsten Gillibrand also stump in the Hawkeye State… And Bernie Sanders holds a rally in Philadelphia.

Data Download: The number of the day is … +1

That was Barack Obama’s margin versus Mitt Romney in the August 2011 NBC/WSJ poll – taken in the aftermath of the debt-ceiling fight with Congress.

Obama had the support of 46 percent of registered voters in that national poll, while Romney got 45 percent in that hypothetical general-election matchup.

Compare that with President Donald Trump’s deficits – at nearly this same point in time – versus Joe Biden (-9), Bernie Sanders (-7), Elizabeth Warren (-5) and Kamala Harris (-1) in the latest NBC/WSJ poll.

By the way, Obama ultimately beat Romney by 4 points in the 2012 general, 51 percent to 47 percent.

Tweet of the day

It's jarring as a reporter every time I hear a young kid ask a presidential candidate about the epidemic of gun violence & school shootings in America.



I felt compelled to share this powerful moment at a campaign stop in Nashua, NH.



This passionate girl gives me hope → https://t.co/LaZswBNHfV — Julia Jester (@JulesJester) July 15, 2019

The Lid: Father, the sleeper has awaken!

Be sure to check out the pod from Friday, when we looked at the popularity of single-payer/Medicare for All — with the help of the sci-fi movie “Dune.”

ICYMI: News clips you shouldn’t miss

The Washington Post writes that Mick Mulvaney is building “an empire for the right wing” as chief of staff.

Despite warnings, it appears that major large-scale deportation enforcement raids aren’t materializing yet.

Peter Baker writes in the New York Times of Trump’s decision to “throw a match” on the nation’s racial tensions over the weekend.

Beto O’Rourke says his family’s ancestors owned slaves.

And support for impeachment is falling, according to our latest NBC/WSJ poll.

Trump agenda: Match thrower

Peter Baker writes in the New York Times of Trump’s decision to “throw a match” on the nation’s racial tensions over the weekend.

A group of young Jews are leading protests against ICE.

2020: A family affair

POLITICO reports on how Trump's 2020 reelection effort is becoming more and more of a family affair.

And the New York Times takes a big look at how Biden became his party’s leading voice against school bussing in the 1970s.

Benjy Sarlin notes that 2020 Democrats are focusing on executive actions that Mitch McConnell wouldn’t be able to block in the Senate.

Steve Bullock is making money in politics the signature issue of his campaign.

Cory Booker says he wants to give aging prisoners a “second look.”

POLITICO looks at how Bernie Sanders’ campaign views its media coverage.

And Sanders says Nancy Pelosi is being “a little” too tough on progressives.