Let's look at a minor case that demonstrates Congress' appropriation powers. The California Navel Orange Commission is a government-sanctioned grower collusion that establishes production quotas so as to restrict supply in order to keep orange prices high. In 1980, the Federal Trade Commission was going to study such agriculture collusions, euphemistically called marketing orders, as a result of increasing criticism from economists, reformers in federal agencies, consumer groups and some orange growers. Big growers descended on Congress to protest the threat to their collusive behavior that an FTC study might create. Congress, as a part of its FTC appropriation, prohibited the agency from monitoring marketing orders. In November 1983, Congress started using a legislative rider to prohibit the Office of Management and Budget from spending any money to review marketing orders.
This example demonstrates that Congress has ultimate spending power and that when it suits favored interest groups, it will use it. Most members of our Republican-controlled House of Representatives say they're against Obamacare. If they really were, they surely would attach a legislative rider or some other legislative device to the Department of Health and Human Services' appropriation bill to ban spending any money on Obamacare; they have the power to. But they don't have the political courage to do so, and their lives are made easier by the pretense that it's the president controlling the spending. And we fall for it.