A Judge for the US District Court for the District of Columbia granted a preliminary injunction Monday, preventing the Trump administration from prohibiting the operation of the popular China-based social media app TikTok.

The order follows President Donald Trump’s signing of Exec. Order No. 13942, which identified TikTok, a short-loop video sharing app presently used by more than 100 million Americans, as a technology firm that poses a risk to national security.

Following the signing, TikTok and its parent company ByteDance filed a lawsuit alleging that the government’s actions violated its First and Fifth Amendment rights and that the executive order exceeded the President and Commerce Secretary’s authority. They had also moved for preliminary injunctive relief, arguing that without such an injunction, they would suffer irreparable harm.

Judge Carl Nichols of the US District Court in Washington, granting the injunction, ruled that the President and the Secretary of Commerce “likely overstepped” their use of presidential emergency powers and “acted in an arbitrary and capricious manner by failing to consider obvious alternatives.”

Nichols is the second federal judge to fully block the Trump administration’s sanctions against TikTok, following a decision by District Court Judge Wendy Beetlestone of the Eastern District of Pennsylvania.