(CNN) Hillary Clinton's 2016 presidential campaign chairman, John Podesta, traveled to Capitol Hill on Tuesday to meet with House investigators digging into Russia's efforts to alter the 2016 elections.
The Russian hack of Podesta's emails played a pivotal role in the election, as WikiLeaks released tens of thousands of his emails one day at a time during last year's presidential campaign.
Podesta told reporters after the meeting he was "happy to cooperate" with the committee's investigation.
Asked if President Barack Obama was aggressive enough in combating Russia's interference, as some have argued he wasn't, Podesta said the administration was "dealing with an unprecedented incidence of the weaponization of the fruits of Russian cyber activity, and I think they were trying to make the best judgments they could on behalf of the American people."
The emails revealed the inner workings of the Clinton campaign, including the micro-machinations and positioning as they decided how to fight the House Benghazi probe, primary challenger Bernie Sanders and a host of other issues.
But the Podesta emails also led to the rise of a stunning series of fake news reports, which falsely alleged that Clinton and Podesta were running a child sex-trafficking ring out of a Washington pizzeria through coded messages falsely alleged to have been in his emails.
A North Carolina man, Edgar Maddison Welch, stormed the pizzeria last December, armed with an assault rifle, saying he was investigating the false "PizzaGate" reports. Welch was sentenced to four years in prison last week, after pleading guilty to assault with a deadly weapon and interstate transportation of a firearm.
House Russia investigators sent out invites last week to six witnesses, three chosen by Republicans and three picked by Democrats.
Congressional investigators have been prying into the effects of fake news on the election and whether anyone from the Trump campaign helped to guide the targeting of that fake news on social media, congressional sources told CNN earlier this month.
Congressional sources have previously told CNN that they plan to invite Brad Parscale, the Trump campaign's digital director, to testify this summer. Parscale did not immediately respond to CNN request for comment Tuesday but previously told CNN on June 16 that he had not been contacted by any investigators -- either federal or Congressional.