Notable Quote of the Day

"[S]ince no incumbent president has been denied his party’s nomination for re-election since 1852, assessing the merits of a president’s primary opponent is a subjective venture. It is, however, clear that any serious candidate challenging a sitting president position themselves as ideologically more doctrinaire than the incumbent. Ronald Reagan’s strike at Gerald Ford in 1976, Ted Kennedy’s 1980 bid against Jimmy Carter, Pat Buchanan’s 1992 challenge to George H.W. Bush all followed this model. And that explains why former Massachusetts Gov. Bill Weld’s primary challenge has generated almost no traction, whereas former Reps. Joe Walsh and former South Carolina Gov. Mark Sanford might do so."

 – Noah Rothman, associate editor of Commentary magazine

Democrats

• Michael Bennet, Joe Biden, Steve Bullock, Pete Buttigieg, and Amy Klobuchar attended the Hawkeye Area Labor Council Labor Day Picnic in Iowa. Bennet, Klobuchar, Tulsi Gabbard, and Marianne Williamson attended the Salute To Labor Chicken Fry Picnic held by the Rock Island County Democratic Party in Illinois.

• Joe Biden said he "wasn't trying to mislead anybody" in response to a Washington Post piece that said the details of a story he told on the campaign trail about a Navy captain who refused a Silver Star medal were not accurate. Biden said, "[T]he story was that he refused the medal because the fella he tried to save — and risked his life saving — died. That’s the beginning, middle and end. The rest of you guys can take it and do what you want with it.”

• Michael Bennet told a crowd in Aspen, Colorado, Friday that he would remain in the race after not qualifying for the third primary debate.

• Bill de Blasio appeared on WMUR’s “Conversation with the Candidate” series in New Hampshire.

• Cory Booker published a piece in Time magazine titled, "A Waitress I Knew Made $2.13 an Hour. I Wish She Lived to Get a Fair Shake in This Economy," in which he called for making it easier to join a union, reinvigorating antitrust agencies, and prioritizing long-term investments in workers over short-term returns to investors.

• Bullock and Gabbard marched in the Dubuque, Iowa, Labor Day Parade Monday.

• Buttigieg's campaign manager Mike Schmuhl said, "Labor Day for us is really going to be a turning point. … It’s when we’ll flip the switch." Schmuhl said the campaign will have 100 staffers in Iowa by the end of September.

• Julián Castro and Bernie Sanders attended a forum as part of the Islamic Society of North America's annual convention in Houston, Texas, on Saturday.

• John Delaney appeared on Hardball with Chris Matthews on MSNBC Friday, where he discussed his campaign strategy and said Iowa's economy is being destroyed by the trade war.

• Kamala Harris published a piece in The Denver Post titled, "Colorado teachers’ pay is unacceptably low. Here’s how I’ll fix it," in which she proposed increasing teacher pay with a mix of federal and state funding and recruiting diverse teachers. 

• Klobuchar released a climate plan Sunday, including the goals of 100% net zero emissions by 2050, participating in the Paris Climate Agreement, and restoring the Clean Power Plan. 

• Wayne Messam helped fill sandbags in Miramar, Florida, ahead of Hurricane Dorian.

• Beto O'Rourke responded to a shooting in Midland-Odessa, by saying, "We don't know how many have been killed. We don't know the motivation. But here's what we do know: This is f***** up." His campaign began selling T-Shirts featuring the final phrase, saying proceeds would go to Moms Demand Action and March for Our Lives.

• Tim Ryan campaigned in Canfield, Ohio, on Saturday, where he told WFMJ there was "no shot" he would drop out of the race after not qualifying for the third primary debate.

• Joe Sestak and Gabbard spoke at a Western Iowa Labor Federation picnic Sunday.

• Tom Steyer said on MSNBC's The Beat with Ari that he would continue running after not qualifying for the third primary debate and criticized the Democratic National Committee for rejecting Iowa's proposed virtual caucus.

• Politico reported that aides to three presidential candidates said they were increasing opposition research against Elizabeth Warren ahead of the third primary debate.

• Marianne Williamson published a piece in The Washington Post titled, "America doesn’t just have a gun crisis. It has a culture crisis," in which she says the country has a culture of violence and calls for a U.S. Department of Peace.

• Axios published a piece saying that, while Andrew Yang ranks 6th in polling average among Democratic presidential candidates, he is 13th in cable news mentions and 14th in "articles written about."

Republicans

• Donald Trump's campaign flew planes with campaign banners over beaches and riverfronts in Detroit, Cleveland, Milwaukee, Erie, and Virginia Beach on Labor Day.

• Joe Walsh was on WTMJ's Wisconsin's Weekend Morning News to discuss why he's running in the Republican primary. He talked about things he thinks Trump has done right and wrong.

• Bill Weld campaigned in New Hampshire, making a stop at the Rotary Club of Manchester’s Cruising Downtown classic car event Saturday.

On the Cusp: Tracking Potential Candidates

• Mark Sanford said in an interview with Fox News about a potential Republican primary bid, "It would be something of a David and Goliath story. I mean it's impossible at many different levels. It'd be a very steep climb. But you know that going in." He planned to announce whether he is running around Labor Day but said Monday he would delay his decision until after Hurricane Dorian passes.

Flashback: September 3, 2015

Donald Trump signed a pledge to support the eventual Republican nominee. Jeb Bush said he would support Trump if he became the Republican nominee.