A private commission led by former President Jimmy Carter and former Secretary of State James A. Baker III is proposing new steps to strengthen state election procedures and recommending that Congress require the political parties to hold four regional presidential primaries in election years rather than allowing states to hold primaries whenever they wish.

The bipartisan panel, called the Commission on Federal Election Reform, said it was responding to flaws in the system exposed by the elections of 2000 and 2004.