The TAKE with Rick Klein

President Donald Trump hasn't done his re-election chances many favors of late. The shutdown has driven his approval rating to within a point of his own low -- the lowest point for any president two years into his first term, going back as far as comparable polls go.

But he may yet get help from some outside dynamics that are being driven, in part, by his polarizing presidency.

Quadrennial worries about a third-party candidate are surfacing due to the musings of former Starbucks CEO Howard Schultz, who tweeted Sunday night, "I am seriously considering running for president as a centrist independent."

Media coverage around his book tour -- he'll be on ABC's "The View" Tuesday -- likely will focus on his calculations around the viability of running in that lane, and in that matter.

Former President Barack Obama strategists, David Axelrod and Dan Pfeiffer, have joined Democratic presidential candidate Julian Castro in publicly urging Schultz to stay off the Ross Perot path. The Texas billionaire is widely blamed for costing former President George H.W. Bush re-election in 1992 when he ran as a third-party candidate.

The Democratic Party in Starbucks' home state of Washington had a blunt message, barista-style, on Twitter: "Don't do it Howard!"

The Republican National Committee, meanwhile, spent a few days last week signaling "undivided" support for Trump, reflecting a reality that could drive Republicans, including former Ohio Gov. John Kasich, into a third-party lane.

The history of runs similar to the one Schultz is considering is mixed, with consequences near-impossible to predict.

But the stakes posed by the Trump presidency make concerns about such things more urgent -- and even more bipartisan -- than usual.

The RUNDOWN with MaryAlice Parks

With the government reopened, House Democrats can refocus on their agenda.

As soon as this week, expect to see investigations and oversight on the Trump administration ramp up and new bills introduced.

According to the latest poll from ABC News/Washington Post, Americans are on board for that too. Six in 10 Americans in the poll, out Sunday, said the new Democratic majority in the House should use its authority to obtain the president's tax returns. Nearly just as many who were surveyed support other investigations of the president.

There has been concern, of course, among some Democrats on the Hill about the optics of so much time spent on a single topic. Is that the best use of government if it means less time devoted to passing legislation?

House Democrats will have some shielding this spring, with more than a dozen Democratic presidential candidates barnstorming the country to lay out their aspirations for the country and the party.

If Sen. Kamala Harris's speech in Oakland, California, on Sunday was any guide, those running will likely spend just as much time -- if not more time -- talking about Democratic Party values and what they want to accomplish, instead of zeroing in on the perceived shortcomings of the current administration.

The TIP with John Verhovek

This week promises, yet again, to vault new names into the 2020 presidential conversation.

Ohio Sen. Sherrod Brown will embark on a "Dignity of Work" listening tour, starting in Cleveland before a three-day swing through Iowa. Brown was vetted to be Hillary Clinton's vice presidential nominee in 2016 and he has a powerful voice as the top Democrat on the Senate Banking Committee. It's a perch that's earned him praise as one of the party's most genuine populist messengers on economic issues.

Former New York City Mayor Mike Bloomberg is slated to be in New Hampshire on Tuesday, after telling a crowd in Virginia last week about a possible 2020 run, "I don't like walking away from challenges."

It seems the massive Democratic field that was expected is coming to fruition. And just as it was with the Republican Party in 2016, assigning an early front-runner is nothing but a fool's errand.

THE PLAYLIST

ABC News' "Start Here" Podcast Monday morning's episode features ABC News Deputy Political director MaryAlice Parks, who explains how both sides are feeling after the president ended the government shutdown without receiving any border wall funding. Then, ABC News Senior National Affairs correspondent Tom Llamas walks us through Roger Stone's indictment and what it means for the Mueller investigation. http://apple.co/2HPocUL

WHAT YOU NEED TO KNOW TODAY

Cliff Sims, a former aide to President Donald Trump and author of "Team of Vipers: My 500 Extraordinary Days in the Trump White House," will appear on ABC's "The View" on Monday.

The House of Representatives will hold a session at 2 p.m.

The Senate will hold a session at 3 p.m.

Former Vice President Joe Biden headlines "An Evening with Vice President Joe Biden" in Fort Lauderdale, Florida.

Sen. Kamala Harris, D-Calif., will participate in a CNN town hall in Des Moines, Iowa.

Marianne Williamson, who said in November that she was exploring a run for the Democratic nomination for president, will make an announcement at a live event in Los Angeles.

Howard Schultz, who announced Sunday night he was considering a run for president in 2020, will be at Barnes & Noble in New York City for a book signing.