What are the advantages of a group (congress) vs. an individual (the president) when it comes to setting policy? what are the disadvatages of both?

The US Congress consists of 2 houses. The House of Representatives, with its 435 members and The Senate, with its 100 members.

In a decision-making process, it is always better to have more participants that could help come up with a better proposal or solution to a certain issue. When it comes to policymaking, having an organized group of individuals who will debate over the country's matters will offer you a greater probability of coming up with better policies in comparison to one single person. The President does have a group of advisors but in the end, it is only he or she which has the last word.

The Supreme Court has the power of Judicial Review. This means that it can invalidate a law that is passed by a Congress by the argument that it goes against a part of The Constitution. It can also invalidate an executive act from the President by considering it to be unlawful.