The defining piece of legislation behind the corporation tax bonanza that has filled Irish State coffers in recent years was the Tax Cuts and Jobs Act (TCJA) passed by the US Congress and signed into law by then-president Donald Trump in December 2017. As Trump returns to the White House this Monday, days before the Irish cabinet is formed to implement a Programme for Government to be largely paid for by the tax contributions of US multinationals, the TCJA now hangs in the balance.  And, much like eight years ago, the Congress will be just as important to watch as…