Opinion writer

* Aaron C. Davis and Shawn Boburg report on why the acting secretary of defense is withdrawing his nomination for the post:

In the months that he has served as President Trump’s acting secretary of defense, Patrick Shanahan has worked to keep domestic violence incidents within his family private. His wife was arrested after punching him in the face, and his son was arrested after a separate incident in which he hit his mother with a baseball bat. Public disclosure of the nearly decade-old episodes would re-traumatize his young adult children, Shanahan said.

On Tuesday, Trump announced in a tweet that Shanahan would not be going through with the nomination process — which had been delayed by an unusually lengthy FBI background check — “so that he can devote more time to his family.”

Shanahan spoke publicly about the incidents in interviews with The Washington Post on Monday and Tuesday.

Chances are that now Trump is just going to keep appointing acting secretaries (and undersecretaries and deputy secretaries) wherever he can to avoid the confirmation process.

* Eliana Johnson reports that the Trump administration is ready to get its war on:

The Trump administration and its domestic political allies are laying the groundwork for a possible confrontation with Iran without the explicit consent of Congress — a public relations campaign that was already well underway before top officials accused the Islamic Republic of attacking a pair of oil tankers last week in the Gulf of Oman.

Over the past few months, senior Trump aides have made the case in public and private that the administration already has the legal authority to take military action against Iran, citing a law nearly two decades old that was originally intended to authorize the war in Afghanistan.

In the latest sign of escalating tensions, national security adviser John Bolton warned Iran in an interview conducted last week and published Monday, “They would be making a big mistake if they doubted the president’s resolve on this.” Acting Secretary of Defense Patrick Shanahan announced on Monday evening that the U.S. was deploying an additional 1,000 troops to the region for “defensive purposes.” And Secretary of State Mike Pompeo jetted to Tampa, Fla., home of Central Command, on Monday evening to huddle with military officials to discuss “regional security concerns and ongoing operations,” according to a State Department spokeswoman.

This all has a familiar ring to it. Can’t quite put my finger on it, but it reminds me of something that happened in, oh, 2003 or so.

* A new Quinnipiac poll in Florida shows Trump trailing every Democratic candidate they tested, with Joe Biden ahead by nine points.

* Stuart Rothenberg explains why Michigan is going to be such an intense battleground in 2020.

* Frank Sharry has a terrific piece urging Democrats to make immigration a key issue in 2020, and explaining how they should do it.

* Julian Zelizer offers a useful explanation of the five pillars of Trump’s reelection bid.

* Jenna Johnson reports on the list of 136 things Amy Klobuchar is planning to do in her first 100 days as president.

*Ryan Cooper details in hair-raising terms just how insane it is that the administration is driving us toward another pointless war in the Middle East.

* Elizabeth Warren, along with Rep. Deb Haaland, introduced a bill to provide universal child care.

* Emily Badger and Quoctrung Bui examine how the housing crisis is being fed by cities that zone large areas only for detached single-family homes.

* Amanda Marcotte explains why Trump feels like he’s winning.

* And Jeet Heer explains why the New York Times hates political cartoons.