The legislation puts new economic restrictions on Russia, North Korea and Iran — and constrains President Trump from easing Russian sanctions on his own.
The sanctions would punish three countries; the bill also aims to prevent President Trump from relaxing sanctions without lawmakers' consent. A House vote is expected on Tuesday.
Donald Trump Jr. found his meeting with Natalia Veselnitskaya a waste of time, but her approach fits into a larger pattern of freelance political activity that has come to characterize Putin's Russia.
The president's eldest son and his former campaign chairman will appear before the Senate Judiciary Committee next Wednesday, where they will be questioned about foreign influence in U.S. elections.
If confirmed, Huntsman would take over a high-profile post amid ongoing probes into Russian meddling in the 2016 election and potential ties between Russian officials and the Trump campaign.
"When you're not doing business, he is a very pleasant person to deal with," says a former Obama administration official. Otherwise, "he's a tough Russian negotiator, deeply suspicious of the U.S."
In addition to defending his son's decision to hold the meeting, President Trump also told Reuters that he had no knowledge of the meeting at the time and only learned of it recently in media reports.