They point to a number of seats where popular incumbents are getting older as their districts grow more Democratic.
That strategy was motivated by another goal, too, when reasonably popular incumbents were saddled with vulnerable running-mates.
But most of the state's black voters are Democrats - yet this did not stop Republican candidates from opposing Florida's three African-American representatives, popular incumbents who will no doubt bring out voters who will vote Democratic "down the line."
Two other popular Republican Representatives, Claudine Schneider of Rhode Island and Bill Schuette in Michigan, are also considering challenges to popular incumbents.
Redistricting this year forced the state's two popular incumbents, a Republican, Ron Marlenee, and a Democrat, Pat Williams, to face each other.
Another race that could be especially close is in Queens, where redistricting has pitted two popular incumbents, Jeremy S. Weinstein, a Democrat, and Frank Padavan, a Republican, against each other, .
But that underlying political shift had been masked as popular Republican incumbents like County Executive Andrew P. O'Rourke continued to hold sway.
In metropolitan France, all incumbent left-wing Presidents are running for a second term in an election which generally favours popular incumbents and anti-government voting.
State Senator George E. Pataki, the Republican Party's endorsed candidate for governor, has built a political career out of toppling popular incumbents and entrenched political machines.