The Note: Trump seeks more power as Congress seeks to give him less The president wants more of it, but Congress is inclined to give him less.

The TAKE with Rick Klein

Among the mantras of President Donald Trump's time in public life -- and continuing through his time in public office -- is that if you say something enough, it becomes real.

That strategy could very well lead to a presidential declaration of a national emergency, with the knowledge that such a move would test both legal and political limits.

Trump said on Thursday he would "probably ... I would almost say definitely" make such a declaration if budget talks don't result in a wall, acknowledging a political off-ramp to what he's arguing is a national-security crisis.

This week has revealed the realities of divided government to Trump, as he's failed to budge Democrats from their opposition to a wall as the price of reopening government.

It has also demonstrated the limits to Republican loyalty -- limits that would be strained further if Trump orders a wall with an end-run around Congress. Sen. Lindsey Graham may be a fan, but Sen. Mitt Romney is not.

This fight, as so many do, comes down to power. The president wants more of it, at a time that Congress is inclined to give him less.

The RUNDOWN with MaryAlice Parks

There's a possibility that the recent headlines about allegations that former campaign staffers for Sen. Bernie Sanders sexually harassed or assaulted female colleagues could undercut the biggest leg-up the Vermont senator's had as he thinks about running again for president. Compared to his Senate colleagues and others who are eyeing their chances, Sanders has had a loyal base and an impressive infrastructure that carried over from his last campaign.

This weekend, one of his unofficial organizing teams boasted that they have 400 house parties scheduled in all 50 states, plus D.C. and Puerto Rico -- sending out an alert and getting people ready. If that grassroots power weakens, the game changes.

Perhaps a victim of his own success, this time around Sanders won't appears so radical on many issues. In Senate leadership now, he has perhaps lost some of the perks that came with being the outsider. It seems almost every Democrat wants to call themselves a progressive these days and half the contenders will have platforms similar to his from the last cycle.

His hurdles, should he get in the race, could be how to distinguish himself and convince enough voters of his electability. A potential front-runner, he could get the scrutiny he avoided last time.

Some of his biggest backers say he has handled these stories well so far by immediately and forcefully apologizing. And it's better any new campaign is formed right from the start, rather than have these issues come up later.

The TIP with John Verhovek

Is climate change an urgent enough issue to help a candidate break through what is expected to be a crowded and raucous field of Democrats in 2020? Washington Gov. Jay Inslee seems to think so.

Inslee, who announced this week that he is heading to New Hampshire later this month for a conversation with college students on the "need to confront climate change," said the issue is the "biggest we face, as a nation and as a people."

But Democrats thinking of taking on Trump in 2020 are mostly focused on economic issues. While they largely agree that climate change is a pressing issue, Inslee needs a compelling argument that will motivate those outside of the party's base to go to the polls, because they may not care about it with the same intensity.

In a March 2018 poll from Quinnipiac, 72 percent of Democrats said they are "very concerned" about climate change, while just 39 percent of Independents and 11 percent of Republicans said the same.

THE PLAYLIST

ABC News' "Start Here" Podcast. Friday morning's episode features ABC News Senior National correspondent Matt Gutman, who tells us about the president's trip to Texas and what life is really like in border towns. ABC News' Trish Turner explains why some Republicans are not so keen to see Trump declare a national emergency over border security. And, ABC News Political Director Rick Klein breaks down why Michael Cohen's upcoming congressional testimony is so significant. http://apple.co/2HPocUL

FiveThirtyEight Politics Podcast. While President Trump's approval rating among self-identified Republicans is sky high, it's hard to ignore his overall political vulnerabilities. In this installment of the FiveThirtyEight Politics podcast, FiveThirtyEight's Perry Bacon Jr. and Marquette University political science professor Julia Azari discuss the history of primary challenges to sitting presidents and the possibility of one against Trump. https://53eig.ht/2M0rQx6

WHAT YOU NEED TO KNOW TODAY

President Trump hosts a roundtable discussion on border security and safe communities with State, local, and community leaders at 2:30 p.m.

Several senators are meeting with their constituents to discuss the effects of the government shutdown on the day most federal employees miss their first paycheck. They include: Sens. Mark Warner and Tim Kaine in Virginia and Catherine Cortez Masto in Nevada.

2020 hopeful Rep. John Delaney is in Iowa today and tomorrow.

Sen. Kamala Harris's book tour continues in New York City. She'll be at the Kaufmann Concert Hall at 7 p.m.

ABC News and FiveThirtyEight are tracking the 2020 presidential field. Here's what the varied cast of Oval Office hopefuls has been up to this week: https://abcn.ws/2TCbJVE