WASHINGTON — As he welcomed Sheikh Tamim bin Hamad al-Thani into town on Monday evening, President Trump ushered Qatar’s 39-year-old ruling emir into the Treasury’s Cash Room, a subtlety-free reinforcement of his eagerness to work with the one of the world’s wealthiest nations.

This “is a fitting tribute to the economic and security partnership between our two nations,” Mr. Trump said of the room, which used to house vaults filled with gold, silver and paper currency. He then pointed to his family members, friends and business associates in attendance.

“This is a who’s who of people in business,” Mr. Trump said, surveying a crowd that contained over 40 business leaders, before adding that working meetings with Tamim, scheduled for Tuesday afternoon, would encompass issues “from defense to purchases and trade, and I know everything’s going to be very positive.”