Twitter CEO Jack Dorsey has added his name to those supporting a presidential pardon for NSA whistleblower Edward Snowden, according to the Pardon Snowden campaign. The campaign, publicly launched on Wednesday, is asking supporters to send emails urging President Obama to lift Snowden’s espionage charges before leaving office. That would allow Snowden, now in voluntary exile in Russia, to return to the U.S.

The campaign, a joint project of Human Rights Watch, Amnesty International, and the American Civil Liberties Union, launched in conjunction with the release of Oliver Stone’s Snowden, which presents the former NSA contractor as something of an American hero.

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Dorsey has shown his support for Snowden in the past. Snowden became active on Twitter in September of 2015, and Dorsey greeted him warmly.

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Snowden’s profile was also almost immediately granted a blue ‘verified’ checkmark. To this day, he follows only one other Twitter account – the NSA’s.

A few other tech leaders have joined the campaign to lift legal sanctions against Snowden. Steve Wozniak, one of the first public figures to refer to Snowden as a hero, has publicly supported the Free Snowden campaign, as has Wikipedia’s Jimmy Wales, and a long list of former government officials, academics, writers, and artists.

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It’s somewhat surprising that more tech CEOs haven’t publicly signed on to the effort. Personal convictions aside, Snowden’s actions arguably strengthened the business environment for U.S. tech companies by creating pushback against government interference in cybersecurity, and increasing consumer trust in U.S. products (at least in the long run).

Most concretely, it’s hard to imagine Apple’s stand against the FBI this past spring being received as well as it was without Snowden’s revelations. But so far, Wozniak is the only prominent Apple affiliate to endorse the effort to bring him back to the U.S.