Congress has many tools that it can use to exert its influence over public policy. Let us look at three of the main tools that it can use.
First, and perhaps most importantly, Congress has the power to make laws. Public policy is created largely by laws that Congress passes. Some of the most important policies in our history have been created by such laws. For example, it was the Civil Rights Act of 1964 that banned discrimination in public places. It was Congress that passed the Clean Air Act that helped to reduce pollution in the US. It was Congress that passed laws creating Social Security and Medicare. It is Congress that passed the “Obamacare” legislation. These things show us that Congress has used the legislative power to exert influence over public policy.
Second, Congress has the “power of the purse.” It is Congress that decides which governmental agencies and programs get money. That is why, for example, the Republicans in the Congress were able to try to kill Obamacare by refusing to fund it. This, too, allows Congress to exert influence in this area.
Finally, Congress has power over the ways in which laws are enforced. Congress shares in the control of the government agencies of the executive branch. It can (as alluded to above) change their funding if it likes. It can hold hearings to criticize their performance and to put pressure on them to change. If Congress does not like the way that laws are being carried out, it can use these tools to try to change things.
In these three ways, Congress can exert significant amounts of power over public policy.