Much of the chatter about next month's midterm election has focused on Republican gains in the Senate, possibly enough to take control of the chamber. The chatter has even taken a triumphalist tone on the right: "We're watching a wave come in," writes columnist Michael Barone. But an examination of governors' races around the country paints a different picture—one that is potentially good for Democrats.

In the United States, wave elections are usually defined in terms of gains in the House and the Senate. In midterm years, strong congressional gains are often accompanied by a net gain in governorships, about two-thirds of which come up for election in the same year. Midterm wave elections generally favor the party in opposition to the president. In the quintessential wave election of 1994, Republicans made net gains of 52 seats in the House and 11 governorships. In 2006, Democrats picked up 31 House seats and 6 governorships. Most recently, in 2010, Republicans picked up 64 House seats and six governorships.

With less than two weeks to go until the election, the overall picture of 36 gubernatorial races is not breaking in the Republicans' direction.

This chart—calculated from HuffPost Pollster data, using the median-based approach of the Princeton Election Consortium—shows elections that are likely to result in a switch in party control or are polling with a margin of five percentage points or less. On the left are the margins by which sitting governors won in 2010. On the right is the median performance of this year's candidates in polls completed in the last two weeks. Red indicates a Republican in the lead, blue indicates a Democrat, and green indicates an independent.

The most remarkable feature of this chart is the widespread weakness in the Republican field. In five states—Alaska, Pennsylvania, Maine, Illinois, and Rhode Island—an independent (Alaskan Bill Walker, who is running on a fusion ticket with Democratic running mate Byron Mallett) and four Democrats hold the lead. In eight states, the candidates are either tied or within 1 percentage point or less of each other. The only state where the Republican is somewhat favored to take a governorship from Democrats is Arkansas, which was won by Mitt Romney in 2012 and where Asa Hutchinson now leads Mike Ross by a median of two percentage points.