CNN's suit was backed by a broad coalition of media groups including Fox, which is controlled by Trump ally Rupert Murdoch and often draws praise from the president.
He said on Tuesday night, "We support CNN in its effort to restore the press credentials of its White House reporter".
So, how is the judge likely to rule? The suspension came after the reporter challenged Trump's portrayal of a caravan of Central American migrants as an "invasion". He also pushed the president to comment about the ongoing investigation into Russian interference in the 2016 election.
Acosta refused to give up a microphone when the president said he didn't want to hear anything more from him.
The Trump administration last week suspended Acosta's "hard pass", which granted him access to the White House. Sanders initially explained the decision by accusing Acosta of making improper physical contact with the intern seeking to grab the microphone.
If CNN reporters behaved professionally and respectfully toward the president, Trump would reciprocate. On Wednesday, the Justice Department filed a response saying that the White House has discretion to "regulate access to the White House for journalists", and argued that "no journalist has a First Amendment right to enter the White House". "We have asked the court for an immediate restraining order requiring the pass to be returned to Jim, and will seek permanent relief as part of this process". The experienced reporter has covered many USA political campaigns including John Kerry in 2004 and the Clinton and Obama campaigns in 2008, as well as reporting on the Iraq War and Hurricane Katrina.
"CNN, who has almost 50 additional hard pass holders, and Mr. Acosta is no more or less special than any other media outlet or reporter with respect to the First Amendment".
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In addition, Mr Whitaker is also a close friend of Donald Trump's 2016 election campaign co-chair Sam Clovis. There's no indication that Mr Whitaker intends to recuse himself from the Russian Federation investigation.
It is incredibly rare to see a news organization suing a president. "This conduct is absolutely unacceptable".
Sarah Sanders, the White House press secretary, dismissed the action as "just more grandstanding from CNN, and we will vigorously defend against this lawsuit".
But here's the truth of the matter: CNN has some 50 other hard passes, and the White House yanked only Mr. Acosta's pass, for one simple reason: He's rude.
"The way you treat Sarah Huckabee is terrible", Trump said. The network claims barring its White House correspondent will have "a unsafe chilling effect".
He drew a comparison with the president's right to exclude reporters from interviews in the Oval Office or to ignore their questions during news conferences.
Read Fox News' full statement: "FOX News supports CNN in its legal effort to regain its White House reporter's press credential".
But I must admit being astonished to find normally-sane media organizations like FOX News, Bloomberg and Gannett issue statements of support, standing behind Jim Acosta.
Judge Andrew Napolitano, the top legal analyst on Trump's favorite network, Fox News, said the same thing on Tuesday. Law firm Ballard Spahr said on behalf of the news organisations: "Whether the news of the day concerns national security, the economy, or the environment, reporters covering the White House must remain free to ask questions".