Are we witnessing the beginning of another great American economic expansion? American history suggests we may be. While headlines focus on inflation, interest rates, federal deficits, and geopolitical uncertainty, another story may ultimately matter more. American businesses are committing hundreds of billions of dollars to artificial intelligence and the infrastructure required to support it, including semiconductors, data centers, advanced manufacturing, energy systems, and digital networks. The technologies dominate today’s headlines, but the investment behind them may ultimately become a far bigger economic story.Technological breakthroughs create possibilities. Capital investment determines whether those possibilities become national prosperity. That simple truth explains why some inventions reshape nations while others become little more than fascinating moments in history. America has never become more prosperous simply because it invented something first. It became more prosperous because it invested in spreading those innovations throughout the economy. That is one of the enduring lessons of American economic history.Every month, economists dissect inflation reports, employment numbers, GDP estimates, and Federal Reserve decisions in an effort to understand where the economy is headed next. Those indicators matter. American history suggests, however, that another set of indicators deserves equal attention: investment cycles. Again and again, they have marked the beginning of America’s greatest economic expansions.