This is not LBJ’s era. Lyndon Johnson had an approval rating of about 70 percent when he routed Goldwater. That’s 25 percentage points above Obama’s! Johnson had the legacy of JFK at his back. More than a third of the nation identified as liberal then. Only a fifth does today.

Goldwater also ran in a time before the two parties were hyper-polarized. Almost half of all Republicans approved of Johnson around Election Day 1964. By comparison, only about one in 10 Democrats approved of Bush on Election Day 2004. The same share of Republicans currently approve of Obama, according to Gallup.

Thus we will not see a sequel to Goldwater. Obama would likely defeat Rick Santorum or Newt Gingrich with relative ease. But even those Republicans would win Texas and most of middle America. Goldwater did not.

George Will posits that the GOP should focus on congressional elections. But challenging an incumbent can reduce his coattails. Modern presidential races can rarely be divorced from Senate contests. Since FDR, no incumbent has also won re-election while losing more than two Senate seats. Republicans need four seats to win back the upper chamber. Republicans will make a race of 2012 because they must…

Political scientist James Campbell, an expert on election forecasting, calculates that the weakest third-year economic growth (change in GDP adjusted for inflation) since 1952 for winning incumbents has been 2.5 percent (Clinton in 1996 and Bush in 2004). The economy grew 1.7 percent in Obama’s third year.