The Affordable Care Act is back under attack. Not as in the repeal-and-replace debates of yore, but in a fresher take from Republican lawmakers who say key parts of the ACA cost taxpayers too much and provide incentive for fraud. Several House Republican leaders have called on two watchdog agencies to investigate, while Sen. Charles Grassley (R-Iowa) fired off more than half a dozen questions in a recent letter to the Centers for Medicare & Medicaid Services. At issue are the ACA’s enhanced subsidies, put in place during the covid-19 pandemic as part of economic recovery legislation. Grassley …