To business groups, manufacturers and veterans of the bank, Mr. Trump appears to be undermining his own trade aspirations by leaving Ex-Im in the lurch.

“I’m not sure he’s really being well served,” said Fred P. Hochberg, the most recent chairman of the bank, who departed in 2017. “If you want to be able to reduce trade deficits and you want to be able to export more, particularly capital goods, that’s what an Export-Import Bank does.”

In recent years, the bank has been barely functional. According to its most recent annual report, Ex-Im authorized just $3.4 billion of mostly short-term export credit in 2017. That is down from the $20 billion that it authorized in 2014, the last year that the bank was fully operational. The report points out that China provided $34 billion in medium- and long-term financing for its exports in 2016, underscoring the competitive disadvantage that the United States faces.

The bank’s crippling has been costly for both companies and their workers, including Boeing, which Mr. Trump has hailed as an emblem of American innovation. In the last two years, two deals involving the sale of its commercial satellites have been canceled and one was significantly delayed given the lack of a quorum at Ex-Im. The stalling of these deals alone has cost the company hundreds of millions of dollars.

“Restoring the Export-Import Bank to full strength is the single best thing Washington can do right now to build on the economic momentum of tax reform, shrink our trade deficits and level the playing field so American workers can win,” said Tim Keating, Boeing’s executive vice president for government operations.

In 2015, General Electric said that it would stop manufacturing certain gas engines in Waukesha, Wis., and that it would instead build a $265 million plant in Canada, which was offering financial support through its version of Ex-Im, known as Export Development Canada. G.E. attributed the move to the lack of United States export financing, saying in a statement that the company “will secure access to Canadian Export Finance to fill the gap from the lapse of the U.S. Export-Import Bank.”