If congress has one party that's in the majority, then that party will likely get more things done in their favor compared to the opposition party. The minority party can slow things down a bit, but not as effectively if they were in the majority.
If congress is evenly split, and there isn't a clear majority, then the amount of new laws and bills passed won't be as much as discussed in the first paragraph. At this point, congress is at a stalemate or deadlock of sorts. This is assuming that the two parties don't work with each other and are on polar opposites of the spectrum. There are instances where the two parties do work together on a number of issues; however, in this current political climate, polarization is higher than ever before.
