A federal judge has dismissed a $50m (£38.6m) lawsuit filed by Democratic presidential hopeful Tulsi Gabbard that accused Google of infringing on her free speech when it briefly suspended her advertising account last year.

The judge, Stephen Wilson of the US District Court for the Central District of California, granted Google’s motion to dismiss the lawsuit on Wednesday because the Gabbard campaign had failed to prove that the First Amendment clause that prohibits the government from curbing free speech applied to Google as a private company.

The Gabbard campaign’s lawsuit failed to establish “how Google’s regulation of its own platform is in any way equivalent to a governmental regulation of an election”, Wilson wrote in his order.

Gabbard, a congressional representative from Hawaii, is still a candidate for the Democratic nomination but has failed to garner any significant support in the early votes or national polls. She did, however, win her first delegate on Tuesday from American Samoa. Officials with the Gabbard campaign did not immediately respond to requests for comment on Wednesday evening.

In July, Gabbard filed what is believed to be the first lawsuit by a presidential candidate against a major technology company. She argued that Google, by regulating political ads on its platform, assumed the traditional role of government in terms of regulating elections and was therefore subject to the First Amendment.

The lawsuit claimed that Google had infringed on her right to free speech when the company suspended the campaign’s advertising account for six hours on June 27 and June 28. The suspension followed a strong performance by Gabbard in the first Democratic presidential debate that had raised her profile. The campaign was unable to advertise to people searching for her name and missed out on an opportunity to raise money or spread her message, the lawsuit claimed.

Her campaign said it was a sign of Google meddling in the election, using its market dominance to influence political discourse.

At the time, Google said that an automated system had flagged the campaign’s advertising account because of suspicious activity and that it had reinstated the account when it realised that the system had acted in error. A Google spokesman declined to comment on the court ruling.