Donald Trump’s appetite for risk might endear him to his Maga base. Bond investors are a more dispassionate breed, however.Concerns over his handling of the economy, in particular his tax and spending plans, which have lifted US debt above $40 trillion for the first time, sent the yield on 30-year United States bonds to their highest level since 2007 this week.Elevated inflation, a function of the US president’s on-off war with Iran, is also souring sentiment.Inflation is bad for bond investors as the value of money deteriorates quicker, meaning investors demand a higher yield for holding debt.To allay concerns and dampen the increase in yields, US treasury secretary Scott Bessent this week announced that the government would double its buyback of US bonds. The intervention came after Washington’s surprise intervention to buy Japanese yen this month, a move that analysts claimed was also designed to support US treasuries.Japanese investors are the biggest holders of US debt and a slide in the value of the yen would have seen many liquidate their US assets.The mini-rally triggered by Bessent’s intervention this week quickly fizzled out with one investor calling it a “band-aid on a bullet hole”.The US government’s move is the “clearest sign yet” that the US is following Japan toward debasing its currency, said Robin Brooks, a senior fellow at the Brookings Institution. The administration is “playing with fire”, he said.The dollar was trading at a three-month low on Friday and was on track for its worst week this month. By buying back bonds, the US government pushes more dollars into circulation, weakening the currency.These bond market machinations are just another sign of how Trump’s tariffs, his on-off war with Iran and, most of all, his unsustainable tax and spending plans are creating economic turbulence at home. He came to power promising to recharge the US economy. Instead he seems to be laying the groundwork for another fiscal crisis.