Everybody, even White House press secretary Robert Gibbs, agrees that Republicans are going to pick up seats in the House and Senate elections this year. The disagreement is about how many.
Some compare 2010 to 1994, when Republicans picked up 52 House seats and won majorities in both houses of Congress for the first time in four decades. That was a reaction to the big government programs of the first two years of the Clinton administration.
Others compare this year to 1982, when Democrats picked up 26 House seats and recaptured effective control of the House two years after Ronald Reagan was elected president. That was a recession year, with unemployment even higher than now.
Let me put another off-year election on the table for comparison: 1966. Like 1994, this wasn't a year of hard economic times. But it was a year when a Democratic president's war in Asia was starting to cause unease and some opposition within his own party, as is happening now.
And it was a year of recoil against the big government programs of Lyndon Johnson's Great Society. The 89th Congress with two-to-one Democratic majorities had passed Medicare, federal aid to education, antipoverty and other landmark legislation.
Democrats only failed, as they have in this Congress, to pass organized labor's No. 1 priority: then repealing section 14(b), which allowed state right-to-work laws, now the card check bill to effectively eliminate the secret ballot in unionization elections.
In 1966, Republicans gained a net 47 seats in the House. That left Democrats with a 246-187 majority but without effective control. That's because 95 of those Democrats were from the South (defined as the 11 Confederate states plus West Virginia, Kentucky and Oklahoma), and almost all voted conservative on most issues.
Republicans actually won the popular vote for the House in the North (defined as the other 36 states) by a 51 percent to 48 percent majority. They have only done so since in three elections -- in 1968 (a virtual carbon copy of 1966 in House races), in their breakthrough year of 1994 and in the post-9/11 year of 2002.
Current polling data suggests that Republicans have a chance of doing so once again in 2010. The realclearpolitics.com's average of recent generic ballot polls -- which party's candidate for the House would you vote for? -- shows Republicans ahead by a historically unprecedented margin of 46 percent to 40 percent.
If those numbers hold, and if they turn out to underpredict Republican performance in the popular vote, as they have in the past, that could mean that Republicans would win a popular vote plurality or majority in the North. Those are two significant ifs, but they're possible.
There is not much doubt about which party will lead in the South. Back in 1966, the South elected only 29 Republican House members (including future President George H.W. Bush) to 95 Democrats. Democrats led in the popular vote there by a 63 percent to 36 percent margin.
In 1992, as Bush was getting thumped in the presidential election, Republicans won a higher percentage of the House popular vote in the South than the North for the first time since Reconstruction. In 1994, they carried the popular vote in the South by 55 percent to 43 percent. They have carried it ever since, even in 2008, when Barack Obama brought out unprecedented numbers of black voters in the South.
Republicans currently hold an 82-to-63 edge in Southern House seats, with eight Democratic-held seats rated likely or leaning Republican by realclearpolitics.com and another 11 Democratic-held Southern seats rated as toss-ups. And 15 more are in play, rated as likely or leaning Democratic.
So Republicans could easily gain 20 seats in the South. But they could gain even more in the North if current numbers hold up.
In 2008, Democrats won the popular vote in the North by 57 percent to 40 percent -- roughly comparable to their lead way back in 1964, the year of Lyndon Johnson's landslide.
If the popular vote in the North should turn out to go narrowly Republican, as it did in 1966, it could be disaster for Democrats. They lost a net 38 seats in the North that year, when they held just about as many seats Northern seats as now. Not a happy scenario for Democrats. But not out of the realm of possibility.