Things are really looking tight in Missouri, where state auditor Claire McCaskill, a Democrat, is running against incumbent senator Jim Talent for a seat in the US Senate. Many pollsters are tipping the race as the tightest of all Senate races for this election. That, in turn, makes it key for control of the Senate as a whole; if the Democrats pick up six seats in the Senate, they will have a majority and control the chamber. Pretty much everyone expects the Democrats to win back a majority in the other chamber of Congress, the House of Representatives, but the Senate still appears to be up for grabs.

Like a college student, McCaskill has pulled an all-nighter of campaigning. Early this morning she was stumping for votes in 24-hour diners across Missouri. Her opponent, meanwhile, is getting only slightly more sleep, and yesterday hosted President Bush in a campaign stop.

While the Senate race itself is neck-and-neck, Missouri’s ballot initiative to protect embryonic stem cell research is looking in better shape. Polls suggest that the initiative is likely to pass, which would make any embryonic stem-cell research that is legal under federal laws also legal in Missouri. It sounds like a no-brainer, but it’s meant to stave off recent challenges by conservatives in the state legislature who want to impose stricter limits on such research.

Looks like it will be a long night in Missouri next Tuesday.