The world's most powerful central bankers are rallying behind Jerome Powell

Many of the world's top central bankers rallied behind Federal Reserve chair Jerome Powell on Tuesday, issuing a rare joint defense after the Trump administration opened a criminal investigation into him.Why it matters: The banking establishment fears Trump's pressure campaign against Powell could destabilize the global economy. If America's central bank loses credibility, every part of the economy — mortgage rates, grocery bills, wages — could suffer.Central bankers worry political meddling erodes trust in the Fed's inflation-fighting and economy-stoking credibility.The U.S. is the world's largest economy, and its economic woes can quickly become everyone else's problems.What they're saying: "We stand in full solidarity with the Federal Reserve System and its Chair Jerome H. Powell," the global central bankers' statement reads. "The independence of central banks is a cornerstone of price, financial and economic stability in the interest of the citizens that we serve."The signatories include the chiefs of the European Central Bank, along with central banks in England, Canada, Sweden, Denmark, Norway, Switzerland, Australia, South Korea and Brazil.The most notable missing signatory was the Bank of Japan; Bloomberg quoted the institution as saying it didn't comment on other central banks' statements. Catch up quick: The Justice Department served the Fed with grand jury subpoenas Friday over cost overruns with the central bank's headquarters renovation.Powell released an extraordinary Sunday video statement calling the investigation a "pretext" to pressure the Fed into cutting interest rates faster.Trump wants the federal funds rates slashed to 1%. The Fed has them at 3.5%–3.75% after cutting 0.75 percentage points since September.With cheaper borrowing, businesses can expand more easily and people often spend more, which can boost the economy — but also run the risk of raising inflation.What's next: Powell's term as chair expires in May, but he can stay on the Fed board as a governor through 2028.Sen. Thom Tillis (R-N.C.), who sits on the closely divided Senate Banking Committee, vowed to oppose the confirmation of any Trump Fed nominees until the investigation ends. That could freeze Trump's pick for Powell's replacement.The Supreme Court will hear oral arguments on Jan. 21 on how much power Trump has to remove Fed officials, a case that could also reshape the central bank's independence.