The bond market is telling us the free lunch is over

For most of this century, rich countries have enjoyed a seemingly free lunch: They could spend money as needed, cut taxes at will and stimulate their way out of problems without paying a price in the form of higher borrowing costs or inflation.The big picture: That era is over. The 145 trillion global bond market is flashing red signals that there's now a price to be paid for governments that indulge their profligate impulses.It reflects a world where supply disruptions are colliding with massive government borrowing needs and the funds required for the AI buildout.The result: Higher inflation and surging demand for capital add up to higher and more volatile interest rates.State of play: In the near term, it becomes more expensive for American homebuyers and companies to borrow. In the medium term, it means a world of thornier tradeoffs for policymakers.Countries facing an economic slump can no longer be confident that they can use fiscal policy to cushion the shocks — it might trigger a painful bond market blowback.By the numbers: The 30-year U.S. Treasury bond yielded 5.06 at Friday's close, after hitting a post-2007 high of 5.18 earlier in the week, up from 4.63 at the end of February.In Japan, the 30-year government bond yield hit 4.15 last week, an all-time record. It came after Prime Minister Sanae Takaichi proposed emergency stimulus to help households and businesses reeling from higher energy prices.Long-term U.K. government debt spiked to 5.85 earlier this month, the highest since 2008, on worries that Prime Minister Keir Starmer could fall and that his successors would act with less fiscal restraint.Between the lines: The global investors who buy longer-term government bonds are accepting two major forms of risk.One is that inflation will whittle away the purchasing power of their returns. The other is that rates will rise in the future due to shifting supply and demand for savings.Both are in play right now. If supply disruptions like the ones over the last few years continue, inflation may be structurally higher than is already priced into markets.What they're saying: Bond markets are pricing the new geoeconomic reality, Daleep Singh, the chief global economist at PGIM, tells Axios. In a world of intensified geopolitical rivalry — where economics has become the main arena of competition — supply-side shocks are going to keep coming.Long-term bond investors are being asked to accept more risk for the same return, Singh, a former top White House, Treasury, and New York Fed official, says. The repricing we're seeing is rational, and it may have further to run.Zoom in: The implications for American households and governments are already evident.The interest rate on a 30-year fixed-rate mortgage has surged from under 6 at the end of February to 6.65 Friday, per Mortgage News Daily.Traders are betting that new Federal Reserve chair Kevin Warsh's first policy move will be to raise rates, not lower them, as inflation expectations are looking increasingly unmoored.If a U.S. downturn does come along, lawmakers will have to weigh the need for fiscal relief against the risk that such a move will counterproductively drive interest rates higher.The bottom line: The endless buffet is over. American lawmakers face harder tradeoffs as they try to deliver an all-candy, no-spinach fiscal diet.