WASHINGTON — Amid a chorus of warnings that the American election system is ground zero for foreign attackers, a panel of leading scholars and election experts issued a sweeping set of recommendations on Thursday for how to make elections more secure.

Several similar reports have been issued lately, but this one is different. It not only carries a blue-ribbon pedigree from the National Academies of Science, Engineering and Medicine, but it also suggests ways to address allegations of domestic voter fraud, which Republicans have leveled for years.

The report notes the significant challenges of securing elections. In 2016, Americans voted in 178,217 precincts and 116,990 polling places. Under the Constitution, each state controls its own election procedures, and officials jealously guard their authority against federal interference. The rules vary so wildly that uniform standards are almost impossible.

Still, many of the report’s proposals can be applied nationwide. Here are six ways the panel says that election security can be improved:

1. Use paper ballots to establish a backup record of each vote.

Even if voter databases and other equipment aren’t connected to the internet, experts said, it will be hard to protect computer systems from cyber threats. As a result, they recommend that by 2020, every voting machine nationwide should generate a backup paper record of each vote. Currently, five states — Georgia, South Carolina, Louisiana, Delaware and New Jersey — and portions of several others do not maintain a paper trail.