First Read is your briefing from Meet the Press and the NBC Political Unit on the day's most important political stories and why they matter.

Congress is barely functioning, but its to-do list keeps getting longer

WASHINGTON — Last week's actions by President Trump to decertify the Iran deal and end key Obamacare subsidies only lengthened the to-do list for a Congress that hasn't achieved much during the first nine months of the Trump Era.

Due to Trump’s decertification of the Iran deal, Congress now has 60 days to reinstate sanctions against Iran, or to modify the law that governs congressional oversight of the deal;

Lawmakers will see if they can try to shore up the Obamacare markets (though Democrats doubt Trump would ever sign such legislation into law after his previous actions to break Obamacare);

The Senate this week considers its 2018 budget resolution, and its fate is uncertain given that it’s the vehicle for the GOP’s tax-reform proposal;

In two months, Congress will again have to pass legislation to keep the government open (with Trump’s border wall being a major snag to get 60 votes in the Senate);

Congress also is considering what to do with the DACA program, which Trump rescinded (and the border wall again is a thorny issue here);

And the GOP is still eyeing tax reform as its major legislative item for the remainder of the 115th Congress.

This would be a daunting list for even the most functional and productive of Congresses. But for this Congress — whose top achievements have been rolling back Obama-era regulations, VA reform and passing ceremonial bills (like the Bob Dole Congressional Gold Medal Act) — this is the equivalent of running a marathon when your previous longest race was just a 5K.

And to govern, Trump and congressional Republicans have to make a choice: Do they try to pass this stuff through their narrow Senate majority (where they can afford only two GOP defections)? Or do they bargain in good faith with Democrats?

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The former route didn't work so well with health care, and the latter seems even harder given the current politics in DC.

By the way, President Trump has lunch with Senate Majority Leader Mitch McConnell at 12:35 pm ET, and this comes after former White House chief strategist Steve Bannon fired off this warning to McConnell and establishment Republicans: "There is a time and season for everything, and right now it's a season of war against the GOP establishment… Yeah, Mitch, the donors aren't happy. They've all left you. We've cut your oxygen off, Mitch."

Why Trump decertifying the Iran deal was such a big deal

“If America would overturn a pact it made to the rest of the world … how can it retain the reputation of a great power?” Don’t miss the New Yorker’s Evan Osnos writing about Trump decertifying the Iran deal: “Gutting a deal that Americans conceived, brokered, and secured would undercut decades of U.S. leadership on non-proliferation."

More: "Decertifying the Iran agreement would fracture the United States’ credibility among its original partners in the deal. It would open a rift with China just as it is weighing whether to join the United States again, this time in negotiating with North Korea. Global Times, a state-backed Chinese newspaper, has asked, ‘If America would overturn a pact it made to the rest of the world, solely because of a transition in government, how can it retain the reputation of a great power?’”

On “Meet the Press” yesterday, UN Ambassador Nikki Haley said, “I think right now you are going to see us stay in the deal.” She added, "What we hope is that we can improve the situation. And that's the goal. So I think right now, we're in the deal to see how we can make it better.”

Steven Bannon on Trump cutting off those Obamacare subsidies: “Gonna blow those exchanges up, right?”

“The White House said it was acting on the recommendation of the Justice Department — that it was canceling illegal federal subsidies that helped sustain the Affordable Care Act. President Trump said what he was doing would hurt the insurance companies only,” the Washington Post’s Aaron Blake writes

“But former top Trump White House aide Stephen K. Bannon told a very different tale this weekend. And it will confirm what every opponent of the move already suspected: that Trump was trying to cause Obamacare to fail. In the midst of playing up Trump's accomplishments Saturday at the ‘Values Voters Summit’ in Washington, Bannon turned to Trump's controversial Obamacare executive order the day before. ‘Then you had Obamacare,’ Bannon said. Trump is ‘not gonna make the [cost-sharing reduction] payments. Gonna blow that thing up. Gonna blow those exchanges up, right?’”

On “Meet the Press” yesterday, Ohio Gov. John Kasich criticized Trump ending these subsidies. “What I don't understand, Chuck, is what are they doing?” he said, per NBC’s Kailani Koenig. “Are they just passing these things and people are praising what the president did because of politics? I mean, do they understand the impact that this has on families, on people?”

Once again, Tillerson doesn’t deny he called Trump a "moron" :

Appearing on CNN yesterday, Secretary of State Rex Tillerson didn’t deny he called President Trump a “moron”:

CNN's JAKE TAPPER: Is it true? Did you call him a moron?TILLERSON: Jake, as I indicated earlier when I was asked about that, I'm not going to deal with that kind of petty stuff.I mean, this is a town that seems to relish gossip, rumor, innuendo, and they feed on it. They feed on one another in a very destructive way.I don't work that way. I don't deal that way. And I'm just not going to dignify the question.

Trump gets subpoena for all documents related to sexual assault allegations

Given the Harvey Weinstein news, this Buzzfeed story is bound to raise eyebrows: “A high-stakes legal showdown is brewing for President Donald Trump, as a woman who said he groped her has subpoenaed all documents from his campaign pertaining to ‘any woman alleging that Donald J. Trump touched her inappropriately.’ The subpoena — whose contents have not been previously reported — was issued in March but entered into the court file last month. The White House did not respond to a request for comment, nor did Trump’s attorney.”

“Summer Zervos, a former contestant on the Trump’s reality TV show The Apprentice, accused Trump of kissing and grabbing her when she went to his bungalow at the Beverly Hills Hotel in 2007 to discuss a possible job at the Trump Organization. After Zervos made the accusation last October, just weeks before the election, Trump denied her accusation and called it a lie. She responded by suing him for defamation. As part of that suit, her lawyers served a subpoena on his campaign, asking that it preserve all documents it had about her. They also asked for ‘all documents’ concerning other women who have accused Trump of groping them.”

Ed Gillespie on Trump: “I don’t know the president”

The New York Times’ Jonathan Martin on Virginia’s gubernatorial race with less than a month to go: “Ed Gillespie, the Republican nominee for Virginia governor, deployed just about every tactical evasion he had learned from a lifetime in politics as he dodged questions about President Trump. Then he finally flashed irritation.”

“‘I don’t know the president,’ Mr. Gillespie said in an interview at his headquarters here when asked whether he thought Mr. Trump was ethical. ‘I’ve not met him.’ If Mr. Gillespie is exasperated with persistent questions about Mr. Trump in the only Southern state that the president lost last year, his Democratic opponent in the governor’s race has his own problems. He is being whipsawed between his instinctive pragmatism and his party’s passion.”