WASHINGTON (AP) — President Donald Trump's former national security adviser Michael Flynn did not sign a mandatory ethics pledge ahead of his forced resignation in February, raising questions about the White House's commitment to the lobbying and ethics rules it imposed as part of the president's promise to "drain the swamp." [...] the White House said he was ousted for failing to fully disclose to the vice president and others the nature of his conversations with the Russian ambassador to the U.S. Since his departure, Flynn registered with the Justice Department as a foreign agent, acknowledging that he had lobbied for a Turkish businessman, performing work that could be viewed as benefiting a foreign government, before going to work in the White House.