WASHINGTON (AP) — A new analysis by the Harvard Business School says there is a lack of genuine competition between Republicans and Democrats, which has enabled the gridlock frustrating many U.S. voters.

The two major U.S. political parties have distorted the rules of elections and the legislative process to avoid competing directly with each other. Instead, many lawmakers focus more on the interests of donors, special interests and primary voters than the country as a whole.

This has created a political leadership that increasingly emphasizes differences rather than common goals. If the competition was healthy between the parties, the analysis said, political leaders and policymakers would be competing to deliver better outcomes on education, health care, infrastructure and taxes, said Michael Porter, a Harvard professor who co-authored the analysis.