So... who didn't see this coming? They had already gotten their tails over their backs that he was an international businessman (didn't need donor $, not going to be beholden to them) from the beginning. They also had brought up the Emoluments Clause several years ago, which means they are scraping the very bottom of their mostly-empty "toolbox."

Democrat Impeachment Investigations Expand to Trump Hotel Clients: ‘Near Raw Bribery’
Penny Starr4 Oct 2019
https://www.breitbart.com/politics/2019/10/04/democrat-impeachment-investigations-expand-to-trump-hotel-clients-near-raw-bribery/
https://archive.is/YDfiQ


As impeachment investigations continue to be taken up in Democrat-controlled House Committees, the Oversight Committee has been looking into an allegation that groups have rented rooms in hotels owned by Donald Trump to gain favor with the president.
Politico reported the Democrats say that Trump could have broken the law by accepting money from “U.S. or foreign governments” at his properties.
“Now we’re looking at near raw bribery,” Rep. Gerry Connolly (D-VA), a House Oversight Committee member who chairs the subcommittee with jurisdiction over Trump’s hotel in Washington, said in the Politico report.“That was the risk from Day One: foreign governments and others trying to seek favor because we know Trump pays attention to this. … It’s an obvious attempt to curry favor with him.”
Politico reported on what sparked yet another investigation:

The investigation began after the committee received information that two entities — a trade association and a foreign government — booked a large quantity of rooms but used only a fraction of them, according to a person familiar with the allegation who isn’t authorized to speak for the committee.
The emoluments clause of the Constitution forbids a president from profiting from foreign governments or receiving any money from the U.S. government except his or her annual salary.

The Politico report included remarks from several Democrats on the committee, including Rep. Ro Khanna, (D-CA).