Ahead of last week’s U.S. Senate vote to recognise the Armenian genocide, Turkey lobbied unsuccessfully to head off the resolution, which passed almost unanimously.

Lobbyists circulated a letter before the vote from Turkey’s ambassador to Washington, Serdar Kılıç, to Congressional offices warning the resolution would “considerably poison the political environment between Turkey and the United States”.

The firm that shared the letter was Venable LLP, which serves as a subcontractor for Greenberg Traurig, according to filings with the U.S. Justice Department. The Turkish government has paid more than $6 million since 2014 to Greenberg Traurig, where Rudy Giuliani had a senior role before leaving to work for President Donald Trump.

Two lobbyists, including a former U.S congressman, made the rounds to offices of prominent Democrats. A former Congressman, Bart Stupak, sent two emails to House Speaker Nancy Pelosi, requesting for the resolution not come to the floor for a vote. A second Venable partner, Loren Aho, forwarded Kılıç’s letter to every Congress member’s chief of staff and spent the next two days reaching out to five Democratic Congressmen.

Ultimately their efforts failed. Pelosi put her support behind the resolution, which passed by 405 votes to 11.

Aykan Erdemir, a senior fellow at the Foundation for Defense of Democracies (FDD) and a former opposition member of the Turkish parliament, blamed Turkish President Recep Tayyip Erdoğan for the failure to head off the resolution.

“Over the last few decades, successive Turkish governments had sympathetic ears among both Democrats and Republicans who helped block various Armenian Genocide resolutions in the Congress,” Erdemir said.

But, he said, Erdoğan had become a “toxic figure in Washington … The number of senators and representatives who are willing to advocate for the Turkish position has dwindled significantly.

“The Erdoğan government’s lobbying efforts have therefore become futile,” he said.

While most historians agree the mass killing of Armenians by Ottoman forces during World War One constituted genocide, Turkey says thousands were killed on both sides of bitter fighting in eastern Anatolia.

All 11 members of Congress who voted against the genocide resolution were Republicans, including Greg Pence, Vice President Mike Pence’s older brother. Six of the 11 belong to the Turkey Caucus, connected to the Turkish Coalition of America, which opposes recognising the genocide.

The Turkish Coalition of America says on its website that it “supports United States’ foreign policy to encourage Armenia to accept Turkey's proposal to establish a historical truth commission”. The organisation’s founder Yalçın Ayaslı once donated $5,200 to one of the 11, Congresswoman Virginia Foxx, according to FEC records.

But most important among the 11 who voted against the resolution are Congressmen Mark Meadows and Mac Thornberry. A former White House official told Politico that Meadows was Trump’s “go-to-guy” in Congress. Meadows said he had voted to protect U.S troops in the Middle East, and later voted for a bill to sanction Turkey for its cross-border offensive in Syria.

Thornberry is meanwhile important as the ranking Republican on the House Armed Services Committee.

Alongside Turkey’s fruitless lobbying efforts, the White House also attempted to stop the Senate’s Armenian genocide vote. Senators Lindsey Graham and Kevin Cramer blocked an earlier vote on the Senate resolution after the White House requested they do so following Erdoğan’s visit to Washington last month. The Turkish Coalition of America website lists Graham, a close Trump ally, as a member of the Congressional Turkey Caucus.

Senator David Perdue had also blocked another vote on the resolution, saying that it would “undermine the administration’s commitment to overcoming real challenges in our bilateral relationship with Turkey”. These concerns echo those of Trump, who frequently touts the importance of maintaining the U.S alliance with Turkey.