President Trump is bashing Senator Hawley as a “second-tier” lawmaker after Mr. Hawley backed a piece of legislation that would ban members of Congress and administration officials from trading stocks. Mr. Hawley and several other Republicans have supported other pieces of legislation in the past, though this is the first time Mr. Trump is lashing out at someone over it. 

The bill in question — the HONEST Act — was brought to the committee by Mr. Hawley and Senate Democrats. Mr. Hawley had previously co-sponsored a bill with Senator Moreno, an Ohio Republican, named the PELOSI Act for the former House speaker, which would have banned members of Congress and immediate family members from trading individual securities. 

The HONEST Act from Messrs. Hawley and Peters expanded that trade ban to the president and vice president, though that prohibition would not take effect until after Mr. Trump leaves the White House. The bill explicitly states that the ban would take effect only once individuals’ next term in office begins, so House members could continue trading until 2027 and senators would be permitted to trade until their next re-election. The ban would not apply to Mr. Trump because he will leave office in 2029. 

“We have an opportunity here today to do something that the public has wanted us to do for decades, and that is to ban members of Congress from profiting on information that, frankly, only members of Congress have in the buying and selling of stock,” Mr. Hawley said as his legislation was called up for a vote. “This bill would finally address that.”

“We have to accept that the American people think that all of us — Democrats and Republicans — are using our positions and our access to enrich ourselves,” Senator Slotkin, a Democrat, said as the panel was discussing the bill. 

The Senate Homeland Security and Governmental Affairs Committee ultimately advanced the bill, with all Democrats and Mr. Hawley voting yes, and all other Republicans voting no. 

Mr. Trump was quick to come out to bash the Missouri senator, who he has praised effusively in the past. “The Democrats, because of our tremendous ACHIEVEMENTS and SUCCESS, have been trying to ‘Target’ me for a long period of time, and they’re using Josh Hawley, who I got elected TWICE, as a pawn to help them,” Mr. Trump posted on Truth Social just hours after the Senate committee advanced the bill. 

“I wonder why Hawley would pass a Bill that Nancy Pelosi is in absolute love with,” Mr. Trump asked rhetorically, referring to Speaker Pelosi’s announcement on Wednesday that she would support the legislation if it came over to the House. 

The president seemed to imply in his post that the passage of this legislation could somehow be used to investigate him, even though — unless he seeks a position as a senator or a House member somewhere down the line — it would never affect him. 

“I don’t think real Republicans want to see their President, who has had unprecedented success, TARGETED, because of the ‘whims’ of a second-tier Senator named Josh Hawley!” Mr. Trump wrote.