(AP) - U.S. Sen. Carl Levin's decision to not seek re-election gives candidates a once-in-a-career opportunity and the Michigan GOP a chance to prove it can win a Senate election. Democrats are left to keep a seat that hasn't been closely contested since the Detroit Tigers won the World Series in 1984. The early focus is on the state's congressional delegation, where at least four members are considered possible candidates. Republicans Justin Amash, Dave Camp and Mike Rogers are being mentioned along with Democrat Gary Peters. Former Republican Secretary of State Terri Lynn Land told The Associated Press on Friday that she's considering running. Republican Rep. Candice Miller isn't running for Senate. Another Republican to rule it out is 2012 Senate candidate and charter schools founder Clark Durant.