According to the Wall Street Journal, Trump appears to have lost patience with Musk after he slammed the Republican Party's massive tax and spending bill. At the same time, Musk is annoyed by Trump's decision to withdraw the nomination of a key ally to head NASA. A senior White House official said Trump was unhappy with Musk's decision to slam the bill he signed, saying the president was baffled by Musk's decision to step up his criticism after working closely with him for four months. The official said Trump's top advisers were caught off guard by Musk's latest offensive. The White House's recent veto of Trump's nominee for NASA administrator Jared Isaacman has also strained the unstable alliance between the two, according to people familiar with the matter. The decision angered Mr. Musk, who complained to colleagues over the weekend that he had donated hundreds of millions of dollars to help Mr. Trump win last year's campaign, only to see Isaacman's nomination canceled, said a person with direct knowledge of the matter. People close to Musk say his disappointment with the NASA incident has made him more willing to actively criticize the tax bill.