Later in the day, the author of the story appeared on Fox news and said that e-mails indicated a push to get people to vote, not to vote a certain way, and said that nothing illegal or unethical was done.

“Given Senator Reid’s work to strengthen the state’s top industry, it should come as no surprise that casino employees support his re-election,” said Kelly Steele, a spokesman for Mr. Reid.

In Woodland Park, Colo., a business owner put a sign up in a shop window that said: “Democrats vote on Wednesday,” said Jon Greenbaum, legal director for the Lawyers’ Committee for Civil Rights Under Law, which directed the Election Protection coalition.

Fliers were sent to voters in a predominantly black neighborhood in Houston that falsely warned them that casting their ballot straight down the Democratic ticket would cancel out their votes.

The fliers were signed by a group called “Black Democratic Trust of Texas.”

In Kansas, voters were reporting that they were receiving calls telling them they could vote on Nov. 3 and that they had to have proof of home ownership to vote. A spokesman for the attorney general said his office had opened an investigation.

“Spreading misinformation about the date of the election seems to have become a perennial weapon of disenfranchisement, and here we go again,” said Tova Wang, a senior democracy fellow at Demos, a voting rights group. “Saying you need proof of home ownership in order to vote is a new wrinkle, and would sadly seem to be particularly aimed at low-income voters or people who have lost their home.”