WASHINGTON -- Fired by one American commander in chief for insubordination, Michael Flynn has now delivered his resignation to another.President Donald Trump had been weighing the fate of his national security adviser, a hard-charging, feather-ruffling retired lieutenant general who just three weeks into the new administration had put himself in the center of a controversy. Flynn resigned late Monday.At issue was Flynn's contact with Moscow's ambassador to the United States. Flynn and Ambassador Sergey Kislyak appear to have discussed U.S. sanctions late last year, raising questions about whether he was freelancing on foreign policy while President Barack Obama was still in office and whether he misled Trump officials about the calls.The center of a storm is a familiar place for Flynn. His military career ended when Obama dismissed him as defense intelligence chief. Flynn claimed he was pushed out for holding tougher views than the Obama administration about Islamic extremism. But a former senior U.S. official who worked with Flynn said the firing was for insubordination, after the Army lieutenant general failed to follow guidance from superiors.Once out of government, he disappeared into the murky world of mid-level defense contractors and international influence peddlers. He shocked his former colleagues a little more than a year later by appearing at a Moscow banquet headlined by Russian President Vladimir Putin. Given a second chance by Trump, Flynn, a lifelong if apolitical Democrat, became a trusted and eager confidant of the Republican candidate, joining anti-Hillary Clinton campaign chants of "Lock Her Up" and tweeting that "Fear of Muslims is RATIONAL."As national security adviser, Flynn required no Senate confirmation vote or public vetting of his record, and his tenure was brief but turbulent.The Washington Post and other U.S. newspapers, citing current and former U.S. officials, reported last week that Flynn made explicit references to U.S. sanctions on Russia in conversations with Kislyak. One of the calls took place on Dec. 29, the day Obama announced new penalties against Russia's top intelligence agencies over allegations they meddled in the U.S. election process to help Trump win.While it's not unusual for incoming administrations to have discussions with foreign governments before taking office, the repeated contacts just as the U.S. was pulling the trigger on sanctions suggests Trump's team might have helped shape Russia's response. They also contradicted denials about such discussions of the sanctions by several Trump administration officials, including Vice President Mike Pence.Flynn later backed off his adamant denials. On Friday, he said he "no recollection" of discussing sanctions policy but "can't be certain," according to an official, who wasn't authorized to speak publicly on the matter and demanded anonymity.He apologized to Pence, who, apparently relying on Flynn's denials, vouched for him on television. In his resignation letter, Flynn said he held numerous calls with the Russian ambassador to the U.S. during the transition and gave "incomplete information" about those discussions to Pence.For days, Trump was publicly and unusually quiet on the matter. While his aides were declaring the president had confidence in Flynn, Trump privately told associates he was troubled by the situation, according to a person who spoke with him recently.INSUBORDINATION:Flynn's sparkling military resume had included key assignments at home and abroad, and high praise from superiors.The son of an Army veteran of World War II and the Korean war, Flynn was commissioned as a second lieutenant in May 1981 after graduating from the University of Rhode Island. He started in intelligence, eventually commanding military intelligence units at the battalion and then brigade level. In the early years of the Iraq war, he was intelligence chief for Joint Special Operations Command, the organization in charge of secret commando units like SEAL Team 6 and Delta Force. He then led intelligence efforts for all U.S. military operations in the Middle East and then took up the top intelligence post on the Joint Staff in the Pentagon.Ian McCulloh, a Johns Hopkins data science specialist, became an admirer of Flynn while working as an Army lieutenant colonel in Afghanistan in 2009. At the time, Flynn ran intelligence for the U.S.-led international coalition in Kabul and was pushing for more creative approaches to targeting Taliban networks, including use of data mining and social network analysis, according to McCulloh."He was pushing for us to think out of the box and try to leverage technology better and innovate," McCulloh said, crediting Flynn for improving the effectiveness of U.S. targeting. "A lot of people didn't like it because it was different."It was typical of the determined, though divisive, approach Flynn would adopt at the Defense Intelligence Agency, which provides military intelligence to commanders and defense policymakers. There, he quickly acquired a reputation as a disruptive force. While some applauded Flynn with forcing a tradition-bound bureaucracy to abandon old habits and seek out new, more effective ways of collecting and analyzing intelligence useful in the fight against extremist groups, others saw his efforts as erratic and his style as prone to grandstanding.In the spring of 2014, after less than two years on the job, he was told to pack his bags.According to Flynn's telling, it was his no-nonsense approach to fighting Islamic extremist groups that caused the rift.A former senior Obama administration official who was consulted during the deliberations disputed that account. Flynn was relieved of his post for insubordination after failing to follow guidance from superiors, including James Clapper, Obama's director of national intelligence, said the official, who asked for anonymity to discuss personnel matters.CIVILIAN LIFE:Plunged into civilian life for the first time in 33 years, Flynn moved quickly to capitalize on his military and intelligence world connections and experience. He did so in an unorthodox way."I didn't walk out like a lot of guys and go to big jobs in Northrup Grumman or Booz Allen or some of these other big companies," Flynn told Foreign Policy magazine in 2015.Instead, he opened his own consulting firm, Flynn Intelligence Group, in Alexandria, Va. He brought in his son, Michael G. Flynn as a top aide, and began assembling a crew of former armed forces veterans with expertise in cyber, logistics and surveillance, and sought out ties with lesser-known figures and companies trying to expand their profiles as contractors in the military and intelligence spheres.One "team" member listed on the firm's site was James Woolsey, President Bill Clinton's former CIA director. Woolsey briefly joined Flynn on Trump's transition team as a senior adviser, but quit in January. Another was lobbyist Robert Kelley.Kelley proved a central player in the Flynn Group's decision to help a Turkish businessman tied to Turkey's government. At the same time that Flynn was advising Trump on national security matters, Kelley was lobbying legislators on behalf of businessman Ekim Alptekin's firm between mid-September and December last year, lobbying documents show.It was an odd match. Flynn has stirred controversy with dire warnings about Islam, calling it a "political ideology" that "definitely hides behind being a religion" and accusing Obama of preventing the U.S. from "discrediting" radical Islam. But his alarms apparently didn't extend to Turkish President Recep Tayyip Erdogan's government as it cracked down on dissent and jailed thousands of opponents after a failed coup last summer. Erdogan's power base is among Turkey's conservative Muslim voters and many affected by his crackdown are secularists.Shortly before Trump's election, Flynn wrote an op-ed saying Turkey needed U.S. support and echoing Erdogan's warnings that a "shady" Turkish Muslim cleric living in Pennsylvania should not be protected by the United States. Erdogan accuses the cleric, Fethullah Gulen, of orchestrating the coup attempt and has requested extradition. Obama officials widely described Turkey's evidence of Gulen's wrongdoing as insufficient.Alptekin, the businessman, told The Associated Press he met Flynn several times starting last summer. He wouldn't detail their conversations. Alptekin said he met mostly with Kelley, a former chief counsel to a congressional subcommittee, who registered with Congress as a lobbyist for Inovo BV, a company Alptekin established in the Netherlands in 2005. Alptekin also is a member of a Turkish economic relations board run by an Erdogan appointee, though he says he has no official relationship with Turkey's government.Kelley said Flynn's consulting firm could help "do something about improving the relations between Turkey and the United States," Alptekin told the AP. He said he didn't consider any need for his firm or Kelley to register with the Justice Department as a "foreign agent in this context" because his firm was "not a government entity."FOREIGN AGENT?Kelley also was a registered foreign agent for the National Mobilization Force, a Turkish-backed militia fighting the Islamic State group in Syria. Documents filed with the Justice Department show Kelley was paid $90,000 to "convey the views" of the armed group to Congress, federal officials and the media.The Justice records do not cite any Kelley affiliation with the Flynn Group. But a December letter from Democratic senators Richard Blumenthal, D-Conn., and Jeanne Shaheen, D-N.H., to top federal intelligence officials raised questions about whether Kelley inappropriately represented the militia on behalf of Flynn's firm, which they said raises "the potential for pressure, coercion, and exploitation by foreign agents."Several ethics experts also said Flynn's firm should have registered with the Justice Department. "If a foreign entity is lobbying Congress on influencing U.S policy, they need to file under the foreign agent act," said Lydia Dennett, an investigator with the Project on Government Oversight, a Washington good government group.Alptekin said Inovo BV paid Flynn's firm "tens of thousands of dollars." Kelley said Flynn's firm made less than $5,000 for its three months of work on behalf of Alptekin's company when he filed a lobbying termination notice to Congress on Dec. 1.Kelley and Flynn Intel Group have not responded to multiple calls and emails from the AP. Flynn said in a statement that Kelley provided to Yahoo News in mid-November that "if I return to government service, my relationship with my company will be severed."The Flynn Intel Group's website no longer operates and AP visits to three northern Virginia locations associated with the firm no longer showed any company activity or identification. Several Flynn Intel Group staffers who worked for the firm and its cyber and flight subsidiaries, FIG Cyber Inc. and FIG Aviation, departed around the November election.BLIMP IN A BOXFlynn had other nontraditional business engagements.In early 2015, he signed on with the cybersecurity firm Palo Alto Networks as a member of its Public Sector Advisory Council comprising retired military officers working as a "sounding board" to answer "the technology needs of the world's governments."He advised Conversion Capital, a venture capital firm specializing in tech-oriented investments. He was briefly listed as a board director of GreenZone Systems, a technology firm headed by another Flynn Intel Group partner, Iranian-American investor Bijan Kian.And then there was Drone Aviation, a firm that makes tethered surveillance drones. Flynn was named vice chairman and a board member in May 2016, and said he would promote the firm's "blimp in a box" concept for military and government use and expand "the role of persistent aerial solutions in the marketplace."The company later won a $400,000 Defense Department contract. Drone Aviation paid Flynn a $36,000 annual salary and awarded him 100,000 shares of restricted stock. He was re-elected to the board after Trump's election but the company's website no longer lists Flynn as a corporate officer.Another venture was Brainwave Science, a Boston company publicizing its use of "brain fingerprinting," scans that the firm claims can be used to assess a person's honesty. Flynn briefly joined the advisory board in February 2016. The firm's concept is disputed by critics and one adviser left the board after media reports surfaced that he pleaded guilty in 1996 to selling stolen biotech material to Russia's spy agency.MEETING PUTINLike many former military officials, Flynn boosted his profile by appearing on television news and talk shows, including several networks connected to foreign governments. They include Qatar-backed Al Jazeera and RT, the news network aligned with the Russian government. He has said he wasn't paid for the appearances.But a December 2015 trip to RT's 10th anniversary celebration would put Flynn in some unique company. An RT video from the Moscow event showed Flynn seated next to Putin and rising during a standing ovation following the Russian leader's address.Flynn has acknowledged being paid for the appearance, but hasn't said who wrote the check or for how much. Flynn's webpage at All American Speakers shows a standard lecture circuit fee in the $30,000-$50,000 range.According to another attendee at the event, Jill Stein, the former Green Party presidential candidate who won 1 percent of the popular vote last November, RT paid for the Moscow event.Stein told the AP she turned down the network's offer to pay for her transportation and stay at Moscow's Hotel Metropol, where the event was held. "I didn't think it was appropriate for a presidential candidate to take money from a foreign government," she said.Before dinner, Flynn was interviewed on international issues by an RT personality. He then joined Stein and others at a front table, seated with Putin and an entourage of aides. Stein said she didn't see Flynn and Putin talk privately at the table.Flynn later told the Post that he had only a brief introduction with Putin. Flynn shrugged off the meeting as "boring."Still, several Democratic House members have asked if Flynn accepted payment from RT and if that is a violation of the federal Emoluments Clause, which prohibits even retired military officers from accepting direct or indirect payments from foreign governments.Flynn was both hopeful and skeptical about Russia relations before joining Trump's administration. In his 2016 book "The Field of Fight," Flynn warned that Russia had joined an "enemy alliance" with Iran. But he also talked publicly of Russia as a possible ally with the U.S. in confronting radical Islam.