By JONATHAN LEMIRE
Associated Press

Donald Trump Jr. has long been his father's id, the brawler who has helped fuel the president's pugilistic instincts and stood firm as one of his fiercest defenders. Now the president's eldest son is at the center of the firestorm over Russian connections swirling around his father's administration and trying to fight off charges that he was open to colluding with Moscow to defeat Hillary Clinton.

Offered Russian help in defeating Hillary Clinton last year, Don Jr. jumped at the offer: "I love it," he emailed.

That was in an email chain the younger Trump released Tuesday in which an associate arranging a June 2016 meeting between the president's son and a Kremlin-linked lawyer promised damaging information about Clinton.

Earlier this week, when news about the meeting first surfaced, Trump Jr. tweeted that he just "had to listen" when he was offered information about his father's Democratic opponent.

Trump Jr., 39, was one of his father's loudest defenders throughout the campaign, his role ascendant at the time of the meeting last summer.

But when his father was elected, Trump Jr. stayed in New York to run the family's sprawling business along with his brother, Eric. And from that vantage point, he has been a loud and constant defender of his father, firing off broadsides on Twitter and never shying away from a fight against the "fake news" media. Just Monday, he retweeted a video of a doctored clip in which the president's face is superimposed over a character shooting a Russian jet bearing a CNN logo.

"One of the best I've seen," Trump Jr. tweeted of the video.

In the email chain released Tuesday, Trump Jr. seemed receptive to receiving damaging information from a foreign government. He released a statement in which he denied any wrongdoing.

His father, conspicuously quiet as details of the meeting have rolled out over the last few days, issued a terse a statement Tuesday in which he said: "My son is a high quality person and I applaud his transparency." Deputy White Press Secretary Sarah Huckabee Sanders said she did not know when the president last spoke to his eldest son.

Trump Jr. has vowed to push back against the charges of collusion, believing that an anti-Trump media is trumping up accusations against him as a way to damage his father and is willfully ignoring his claim that he did not receive any information from the Russian lawyer, according to several of the real estate heir's confidants.

He has settled on a strategy out of his father's playbook: a strong counter-attack. He released the emails himself - although just minutes before they were set to be published by The New York Times - and appeared on Sean Hannity's program late Tuesday to defend himself in a typically Trump-friendly space.

Trump Jr. and his father were not always close: The younger Trump, who admits to a wild post-college period before he cut back on his drinking, didn't speak to his father for a year after Trump divorced his mother, Ivana. But he grew into an executive role at the Trump Organization, was a co-star on "The Apprentice" and during his father's campaign was an active campaign presence, criss-crossing the country to speak in small towns and delivering a well-received speech at the national convention in Cleveland.

An avid big game hunter, he also was seen as the campaign's emissary to Trump's most conservative followers, particularly those online, due to his aggressive pushbacks against Democrats and the media, as well as an embrace of the conservative fringe ethos of the alt-right.

Last fall, Trump Jr. tweeted images of Pepe the Frog, a cartoon character whose image has been used by white supremacists, as well as imagery which likened Syrian refugees to poisonous Skittles candy.

And while he and his brother say they have instituted a firewall that separates his father's business from the White House, Trump Jr. has eagerly defended his father's presidency, live-tweeting attacks on ex-FBI Director James Comey's Senate testimony and amplifying his father's war on unfavorable news coverage.

"Don was an asset to the campaign, a sportsman, an entrepreneur, a guy's guy," said Sam Nunberg, a former Trump campaign adviser. "And Don is a true conservative who really understood the movement his father started and its messages."

The sprawling Russia investigation can only be a distraction to Trump Jr. as the Trump Organization is rolling out two new hotel chains in the U.S. that are a break from the opulent high-priced hotels the company now owns. With both new chains, the Trump Organization is neither building nor financing the hotels and so will need to partner with real estate developers and investors. That has drawn criticism from government ethics experts who worry these partners may be hoping to gain favor with the new administration on policy or regulation in cutting deals with the president's company.

Associated Press Business Writer Bernard Condon contributed reporting.