Here's a situation that points up the difficulties that a national party machine has, in trying to shape its party's campaign for the U.S. Senate.
Politico reports about statements made by Republican Senate leaders about Senator Jim Bunning of Kentucky, whose second term ends next year. That article speculates that those leaders are trying to ease Bunning out of the Senate.
Each party organizes a committee in each house of Congress, to coordinate the campaigns of its candidates. Those committees raise money, that is doled out to individual campaigns, to supplement each candidate's own fundraising. Senator John Cornyn, Republican of Texas, currently chairs his party's campaign committee in the upper house.
However, an incumbent's decision on whether to seek reelection is entirely his or her own. And I suspect that hints, however subtle, that an incumbent should contemplate retirement, are likely to backfire.
Of course, here in southeastern Pennsylvania, we have a connection with Senator Bunning, as I described here. Although I was in Minnesota when his place of business was the Phillies' pitcher's mound rather than the Senate Chamber, I can't help but take Bunning's side, in any dispute with fellow members of our party.