Final answer:
Social sorting has led to increased party polarization in American democracy, resulting in the parties becoming more dissimilar from each other. The negative impact of this polarization is increased interparty conflict and a decrease in bipartisanship.
Step-by-step explanation:
The implication of social sorting for party polarization and American democracy is that it has led to increased ideological distance between the two major political parties. As voters have started identifying more with national-level party politics, they are more likely to choose parties that consistently represent their national ideals. This has resulted in the parties becoming more dissimilar from each other, with fewer moderates being elected to office. The negative impact of this polarization is increased interparty conflict and a decrease in bipartisanship.