President Donald Trump suggested that a $2.5 billion renovation plan at the Federal Reserve might be sufficient cause to fire Fed Chair Jerome Powell, an escalation of his recent attacks against the central banker.

US President Donald Trump this week escalated attacks on central bank chair Jerome Powell, suggesting he could be dismissed for "fraud" over his handling of a renovation project at the Federal Reserve's headquarters.

Three things can simultaneously be true: that it would be reasonable for the Federal Reserve to cut interest rates; that its headquarters renovation is too expensive; and that the Trump administration's attacks show why central banks are designed to be independent in the first place.