The Illinois senator didn’t show up on the polling charts until 24 months before the 2008 elections, just two months before his official announcement in Springfield, Ill. And even then he trailed the presumptive nominee, Hillary Clinton, 29-22, as the choice for the Democratic presidential nomination.

To illustrate how accurate such polls were in those medieval days of this century, someone named Al Gore was the third choice among Democrats then, followed closely by — don’t laugh now — John Edwards.

The same predictive accuracy may well apply to Tuesday’s CNN/Public Opinion Poll showing that on only his 392d day in office, a majority of Americans (52%) have already decided to deny Obama a second term in office about 980 days or so from now.

All of which is vivid proof of how quickly the modern American presidential selection process and landscape is changing, making traditional patterns of political prediction as reliable as Prius brakes.