In November 2008, 33 states hold regularly-scheduled U.S. Senate elections. There will be at least one minor party or independent candidate for U.S. Senate on the ballot in at least 22 states.
States in which there definitely will be no minor party or independent candidates for U.S. Senate on the ballot are Alabama, Mississippi, New Mexico, South Dakota, West Virginia, and Wyoming. There are ballot-qualified minor parties in all those states except Alabama, but those parties all chose not to run anyone for U.S. Senate. In New Mexico, though, even a ballot-qualified minor party would have needed a substantial petition.
It is uncertain if there will be a minor party or independent candidate for U.S. Senate this year in Delaware, Kentucky, Louisiana, Montana, and Rhode Island. In Montana, the only possibility is for independent candidate Steve Kelly to win his pending ballot access lawsuit.
Last time this set of Senate seats was up was in 2002. In 2002, there was at least one minor party or independent candidate on the ballot for U.S. Senate in all states except Arkansas, Kentucky, Maine, New Mexico, Rhode Island, West Virginia, and Wyoming.