Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

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.

Trump takes a wrecking ball to two Obama legacies

WASHINGTON — Despite his business career as a builder, Donald Trump’s first year as president has focused more on dismantling his predecessor’s achievements — with less focus on how to replace them. This week gives us two key examples.

At 11:15 am ET, Trump will sign an executive order that experts believe “could rattle the Affordable Care Act’s private insurance markets by allowing a proliferation of cheaper, less comprehensive plans that would undermine rules about who and what insurers must cover,” the Huffington Post’s Jonathan Cohn writes.

“The new, less regulated insurance plans could provide an attractive alternative to consumers who don’t expect to have large medical bills and who are frustrated with the high premiums they pay for policies today. At the same time, comprehensive coverage could become harder and eventually even impossible to find, especially for people with pre-existing conditions.”

Then tomorrow, Trump is expected to announce that he’s decertifying the Iran nuclear deal, despite almost every observer and national-security expert — including in Trump’s own cabinet — saying that Iran has abided by the deal.

Why is Trump taking this action, which would kick to Congress whether the United States would effectively withdraw from the deal? As the Washington Post reports, he threw a fit because his advisers believed the deal had its benefits.

“He was incensed by the arguments of Secretary of State Rex Tillerson, Defense Secretary Jim Mattis and others that the landmark 2015 deal, while flawed, offered stability and other benefits. He did not want to certify to Congress that the agreement remained in the vital U.S. national security interest and that Iran was meeting its obligations. He did not think either was true,” the Post says. “‘He threw a fit,’ said one person familiar with the meeting. ‘. . . He was furious. Really furious. It’s clear he felt jammed.’”

More from the Post: “So White House national security adviser H.R. McMaster and other senior advisers came up with a plan — one aimed at accommodating Trump’s loathing of the Iran deal as ‘an embarrassment’ without killing it outright.”

Let that sink in: The president is taking a course of action on an international agreement because it didn’t align with his personal opinion. And his advisers — who disagreed — tried to come up with a solution that didn’t kill the deal. At least not immediately.

Now the question turns to: So what will Trump build in its place? NBC’s Vivian Salama, Andrea Mitchell and Carol Lee report that the Trump administration wants to use the congressional debate to work on a new deal that cracks down on Iran’s missile program and its destabilizing activities in the Middle East.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

But: “Britain, France and Germany, along with the European Union’s foreign policy chief, have argued to Congress and the Trump administration that the deal cannot be redone. Iran has said the same,” the Post writes.

Reminder: America’s European allies — as well as members of Trump’s cabinet — believe Iran has been in compliance with the nuclear deal

As we wrote yesterday, if Trump decertifies the Iran deal, it would put him at odds with much of the rest of the world — as well as members of his own national security team:

Defense Secretary James Mattis

ANGUS KING: Secretary Mattis, very quick, short-answer question -- do you believe it's in our national security interest at the present time to remain in the JCPOA [Iran nuclear deal]? That's a yes or no question.MATTIS: Yes, senator, I do. (October 3, 2017 Senate Armed Services Committee hearing)

Joint Chiefs Chairman Joseph Dunford

“Iran is not in material breach of the agreement, and I do believe the agreement to date has delayed the development of a nuclear capability by Iran.” (October 3, 2017 Senate Armed Services Committee hearing)

British Prime Minister Theresa May

“The [prime minister] reaffirmed the UK's strong commitment to the deal alongside our European partners, saying it was vitally important for regional security.” (A May spokesperson’s readout of her call last night with Trump)

German Foreign Minister Sigmar Gabriel

“[W]e do not want to see this agreement damaged… We urge the White House not to call into question such an important achievement that has improved our security." (Reuters)

In addition to those comments, Trump’s administration has already certified the agreement twice (on April 18 and July 17), and the International Atomic Energy Agency says Iran is abiding by the agreement.

Sasse becomes the latest GOP senator to criticize Trump

After a series of tweets attacking the news media — “Network news has become so partisan, distorted and fake that licenses must be challenged and, if appropriate, revoked. Not fair to public!” Trump said in one — Sen. Ben Sasse, R-Neb., released this statement:

“Mr. President: Words spoken by the President of the United States matter. Are you tonight recanting of the oath you took on January 20th to preserve, protect, and defend the First Amendment?”

Trump: FEMA and first responders can’t stay in Puerto Rico forever

Meanwhile, Trump fired off this three tweets on Puerto Rico:

"Puerto Rico survived the Hurricanes, now a financial crisis looms largely of their own making." says Sharyl Attkisson. A total lack of.....

...accountability say the Governor. Electric and all infrastructure was disaster before hurricanes. Congress to decide how much to spend....

...We cannot keep FEMA, the Military & the First Responders, who have been amazing (under the most difficult circumstances) in P.R. forever!

Obama to stump for Northam next week

Former President Barack Obama will stump in Virginia next week for Democratic gubernatorial candidate Ralph Northam, the Northam campaign announced Wednesday. The rally – Obama's first public campaign event after leaving office – will take place in Richmond on October 19.

And the announcement comes a day after the Northam camp said that former Vice President Joe Biden will appear at a workforce-development roundtable for the Democratic candidate this Saturday.

On the Republican side, former President George W. Bush will headline fundraisers for Gillespie later this month, and Vice President Mike Pence is set to appear at a rally for the GOP candidate this Saturday.