The cases and charges, each announced over the past month, count among hundreds involving a slew of programs enacted by Congress in the darkest days of the coronavirus pandemic — money dispatched with such an urgency at the time that it is now putting Washington’s watchdogs to the test.

Roughly two years after lawmakers approved their first tranche of rescue funds, the U.S. government is grappling with an unprecedented challenge: how to oversee its own historic stimulus effort. Totaling nearly $6 trillion, the loans, grants, direct checks and other emergency assistance summed to more than the entire federal budget in the fiscal year before the coronavirus arrived, creating a unique and long-term strain on the nation’s policymakers to ensure the funds have been put to good use.

Policymakers and economists widely agree that the investments helped rescue the U.S. economy from the worst crisis since the Great Depression, aiding out-of-work Americans and saving businesses from shuttering for good. But the money remains hard to track. There are lingering questions as to whether it benefited those who needed it the most. And the aid continues to be a ripe target for criminals nationwide, the full extent of which is only beginning to come to light.