Republicans believe that free markets and individual achievement are the primary factors behind economic prosperity. Republicans frequently advocate in favor of fiscal conservatism during Democratic administrations; however, they have shown themselves willing to increase federal debt when they are in charge of the government (the implementation of the Bush tax cuts, Medicare Part D and the Tax Cuts and Jobs Act of 2017 are examples of this willingness). Despite pledges to roll back government spending, Republican administrations have, since the late 1960s, sustained or increased previous levels of government spending.