Republican-held Senate seats in Virginia, Colorado, New Mexico, North Carolina, Alaska, New Hampshire and Oregon will almost certainly flip to the Democrats. Minnesota (with comedian Al Franken trying to upset Republican Norm Coleman) is closer, but still a likely Democratic gain. But watch the next tier of races, in which Republican incumbents are trying to hold their jobs in Mississippi, Georgia and Kentucky. Losses in one or more of these would be jarring for Republicans. In House races, watch to see if any contests in states with early poll closings see a loss by a Republican incumbent who was never discussed as in real danger. If that happens, it is a canary-in-the-coal-mine sign that a tidal wave is washing over the GOP, likely to produce a net Democratic gain of over 30 seats. And yes, it would be such a huge event that you wouldn't even notice the mixed metaphors.