But even after Attorney General William Barr said Sunday that Mueller found no evidence President Donald Trump's campaign had colluded with the Russian government to sway the 2016 election, Goldstone said it wasn't a wasted effort.
"I hope that everyone will realize this was not a witch hunt. This was a very, very valid exercise in democracy," Goldstone told The Associated Press on Tuesday. "But at the end of the day if the findings are as we believe they are and there's no reason to think otherwise, then really people should move on."
"Witch hunt" was a term used repeatedly by Trump to deride Mueller's investigation. In brokering the Trump Tower meeting over email, Goldstone said Russian lawyer Natalia Veselnitskaya had documents that could "incriminate" Democrat Hillary Clinton and they were being shared as part of the Russian government's support of the Trump campaign. Trump Jr. eagerly took the meeting, which also was attended by campaign chairman Paul Manafort and Trump son-in-law Jared Kushner. The participants would later say the meeting was a bust, taken up with discussion of Russian adoption and U.S. sanctions.
"So to me it was a classic bait-and-switch that took on a life of its own because Russia became this hot-button topic," Goldstone said. Goldstone came to know the Trumps while representing Azerbaijan-born singer Emin, whose father had partnered with the Trumps on the 2013 Miss Universe pageant in Moscow. He said even though he felt the meeting he helped set up was immaterial, testifying before the grand jury was terrifying.
"Even though you deep down and fundamentally you know you've done nothing wrong, you believe you've done nothing wrong, you're warned by so many people that the reason people get tripped up isn't because they've done anything wrong," he said. "It's that inadvertently or maybe on purpose they lie, they forget, they say something that isn't consistent. And suddenly you've got a perjury case. So it makes you hypersensitive."
Goldstone also testified before Congress behind closed doors and says he's still not done on Capitol Hill. He is one of dozens who have been asked to testify before the House Judiciary Committee chaired by Democratic Rep. Jerry Nadler of New York.
"I have cooperated in a voluntary capacity with five committees or five inquiries. There's no reason not to do six," Goldstone said.