When President Donald Trump claimed in a Monday cabinet meeting that “we never gave a commitment to the Kurds,” the U.S. ally recently abandoned in northern Syria, an immediate rebuke came from a source not easily dismissed as “fake news”: a Fox News correspondent.

“Not true,” Jennifer Griffin tweeted. “According to a former top senior military adviser to President Trump, ‘We told them over and over ‘We are your friends. We will never leave you.’”

The tweet was a sign of Griffin’s emergence as the reporter most willing to fact-check and contradict Trump’s claims about Syria to an audience accustomed to less critical coverage. Griffin’s early revelation that Trump had “gone off script” in his fateful phone call with Turkish President Recep Tayyip Erdogan before Turkey’s invasion of Syria gave many conservatives the grist to question Trump’s actions. And her continued efforts to push back against Trump’s assertions have thwarted the White House’s efforts to portray the Turkish action against the Kurds as inevitable…

In another widely shared tweet, Griffin last week accused Trump of pushing a “Turkish talking point” that the Kurdistan Workers’ Party (PKK) is “a greater threat than ISIS.” On Sunday, she posted several tweets from a call with Kurdish general Mazloum Kobani Abdi, a key U.S. partner in the fight against ISIS, who accused accused Turkey of ignoring a cease fire and continuing its “ethnic cleansing” in northern Syria.