Some of the largest defense contractors say they're seeking to work with Congress to change or reverse a portion of the 2017 tax legislation that would, effective in 2022, require companies to delay writing off research and development costs. Companies today can immediately deduct research and development expenditures, according to a recent letter from the R&D Coalition to Capitol Hill . "However, at the end of 2021, businesses will be required to amortize these expenditures over a period of years,...