The Note: Primary challengers tempt Republicans to bolt from Trump

Former Rep.Joe Walsh gave his first interview as a 2020 Republican candidate.

The TAKE with Rick Klein

Here are some of the things the newest entry into the Republican presidential primary is saying about President Donald Trump: "nuts," "erratic," "narcissist," "bully," "indecent," "coward," "cruel," "bigoted," "disloyal," "un-American," "a child," "completely unfit" and "incompetent."

All of that came in former Rep. Joe Walsh's first interview as a 2020 candidate on ABC's "This Week" on Sunday.

Rather than one big GOP Trump rival in the primary, there will likely be several smaller ones. Walsh joins former Gov. Bill Weld in the race, with former Rep. Mark Sanford and former Gov. John Kasich set to decide on their own runs in the next few weeks.

From Greenland to guns and tweets to tariffs, there's no shortage of issues in the news around which Republicans may want other options.

Even if they don't add up to a serious threat to the president's renomination -- and there are no signs that any Trump rival will make him sweat even a single primary or caucus -- primary challenges have a history of weakening incumbents and exposing vulnerabilities.

Walsh is no proven vote-getter, and his own history of controversial statements and actions could undermine early campaign credibility. But he knows how to grab media attention, and calling the president names could be one way to get Trump to react.

Walsh, like Weld, is getting in unafraid about the possibility of harming Republican efforts to hold the White House.

The RUNDOWN with MaryAlice Parks

Democratic presidential candidates hoping to qualify for the third primary debate next month have three more days to qualify.

The requirements, set by the Democratic National Committee, remain: Candidates must garner 2% in four approved national or early-state polls and have 130,000 unique donors.

Ten candidates so far have qualified, and two more are on the cusp: businessman Tom Steyer and Rep. Tulsi Gabbard, who both have started petitioning the DNC to count additional polls in which they performed well.

Notably, at least one sitting senator and one sitting governor likely will not hit the thresholds, although since the benchmarks stay the same for October's debate, they could have more luck later on.

Unsurprisingly, the Democratic Party has taken a beating from the candidates over these rules. Some campaigns have claimed the standards unfairly advantage candidates who have richer or more activist bases.

In a blistering statement over the weekend at the DNC's summer meeting, Colorado Sen. Michael Bennet said: "We're rewarding celebrity candidates with millions of Twitter followers, billionaires who buy their way onto the debate stage and candidates who have been running for president for years. It forces campaigns to fork over millions of dollars to Facebook -- the same platform that let the Russians interfere in 2016 -- instead of harnessing the resources to talk to voters."

With several polling outlets likely to release additional numbers this week, Democratic voters and campaigns should get some clarity soon.

The TIP with Benjamin Siegel

Mark Sanford, the former South Carolina governor and congressman, is scheduled to travel to Iowa on Wednesday and Thursday as he continues to weigh a primary challenge against Trump.

While former Republican congressman and radio host Joe Walsh's announced his primary challenge to Trump on Sunday, Sanford still plans to decide on running for president by Labor Day.

Like Walsh, Sanford said he would take on Trump from the right and question his record on fiscal issues -- just days after the Congressional Budget Office projected the federal budget deficit would top $1 trillion next year.

While some Republican voters may be receptive to their calls for fiscal restraint, it's unlikely that would translate to opposition to Trump: Nearly 9 in 10 Republicans approve of the president's performance in office, according to a recent Fox News poll, among the highest levels of support Trump has received in office.

That math -- and the nature of the Republican Party in 2019 -- isn't lost on Sanford as he weighs his options. Despite his long -- and colorful -- political career in South Carolina, he lost his primary to a Trump-aligned challenger last year after the president criticized him and questioned his loyalty on Twitter.

"I have been dead a couple of times in politics. It teaches you, you don't fear death," he said on MSNBC on Sunday.

THE PLAYLIST

ABC News' "Start Here" podcast. Monday morning's episode features ABC News Chief White House Correspondent Jonathan Karl, who checks in from France to recap Trump's busy weekend at the G-7 summit. Then ABC News' Rachel Scott explains why former Congressman Joe Walsh could give the president some trouble in his reelection bid. http://apple.co/2HPocUL

WHAT YOU NEED TO KNOW TODAY

  • President Donald Trump participates in meetings at the G-7 summit in Biarritz, France, before traveling back to Washington Monday night.
  • Former Rep. Beto O'Rourke and Rep. Tim Ryan, D-Ohio, campaign in South Carolina .
  • Sen. Cory Booker, D-N.J., campaigns in New Mexico.
  • Former Housing and Urban Development Secretary Julián Castro campaigns in Nevada.
  • Sen. Amy Klobuchar, D-Minn., Marianne Williamson and Andrew Yang campaign in New Hampshire.
  • Sen. Bernie Sanders, I-Vt., campaigns in Pennsylvania.
  • Download the ABC News app and select "The Note" as an item of interest to receive the day's sharpest political analysis.

    The Note is a daily ABC News feature that highlights the key political moments of the day ahead. Please check back tomorrow for the latest.