What happened to Chuck?

Senate Finance Committee Chairman Chuck Grassley (R-Iowa) condemned President Trump's new tariffs on Mexico late Thursday, calling the move a "misuse" of presidential tariff authority and cautioning the levies could derail passage of the United States-Mexico-Canada Agreement (USMCA).

"Trade policy and border security are separate issues. This is a misuse of presidential tariff authority and counter to congressional intent," Grassley said in a statement.

  The Hill

Misuse of presidential tariff authority. Sounds like a possible impeachable offense to me.

Careful there, Chuck. You'll find yourself on the wrong end of a tweet.

Trump announced he would impose the tariffs to pressure Mexico to stop the flow of migrants into the U.S. via the southern border.

[...]

[Grassley] cautioned that following through on Trump's tariff threat "would seriously jeopardize passage of USMCA," a revision of the North American Free Trade Agreement (NAFTA).

"I support nearly every one of President Trump’s immigration policies, but this is not one of them," he added.

[...]

Dow futures plummeted more than 200 points on Thursday evening after the president announced the new tariffs.

Grassley had previously threatened to derail Trump's central trade achievement over continued steel and aluminum tariffs. Last week, Trump hinted that he had reached a deal to drop those tariffs, paving the way for the USMCA in the Senate.

Even with Grassley's approval, Trump will face a hurdle passing the agreement in the House, where Speaker Nancy Pelosi (D-Calif.) has insisted on labor and enforcement improvements to the deal.

Earlier Thursday, Trump formally kicked off the approval process for the deal, setting off a timeline for its passage in Congress.

Pelosi derided the decision, meant to pressure Congress to pass the deal, saying it “indicates a lack of knowledge on the part of the administration on the policy and process to pass a trade agreement.”

...but hey, do what you want...you will anyway.