Washington Post: Trump revealed highly classified information to Russian foreign minister and ambassador.

“President Trump revealed highly classified information to the Russian foreign minister and ambassador in a White House meeting last week, according to current and former U.S. officials, who said Trump’s disclosures jeopardized a critical source of intelligence on the Islamic State.
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For almost anyone in government, discussing such matters with an adversary would be illegal. As president, Trump has broad authority to declassify government secrets, making it unlikely that his disclosures broke the law.
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[O]fficials expressed concern about Trump’s handling of sensitive information as well as his grasp of the potential consequences. Exposure of an intelligence stream that has provided critical insight into the Islamic State, they said, could hinder the United States’ and its allies’ ability to detect future threats.”