'POLITICAL TIMING'
Turkey accepts that many Armenians living in the Ottoman Empire were killed in clashes with Ottoman forces during World War One, but contests the figures and denies that the killings were orchestrated or constitute genocide.
"They took advantage of the current political climate against Turkey in Washington to pass this resolution," a source close to the presidency said. Like the other officials, he spoke on condition of anonymity.
Trump has expressed sympathy for Turkey over its purchase of Russian defence systems, blaming his predecessor for not selling Ankara U.S. Patriot missiles. His eagerness to pull U.S. forces out of Syria also aligned with Erdogan's plan to send troops across the border to drive back the YPG.
However, last month Trump threatened to "obliterate" Turkey's economy, and Trump sent Erdogan a letter on the day the offensive started warning him he could be responsible for "slaughtering thousands of people".
"Don't be a tough guy. Don't be a fool!" Trump wrote.
A Turkish security official cited Trump's letter, along with the votes in Congress, as damaging: "If the atmosphere doesn't change, there won't be any point to this visit".
Erdogan himself said three weeks ago he could no longer keep up with Trump's blizzard of tweets.
Still, for Ankara, Trump remains the best hope of salvaging a partnership between two countries that, despite their difficulties, want to quadruple their annual trade to $100 billion.
"The two leaders have a good relationship," the source close to the presidency said. "President Trump wants to have good relations with Turkey in spite of his own establishment."
