I have seen this tactic used ever since the first major open primary contest in S. Carolina in which it became apparent that Indie's and Republicans were crossing over to vote for Obama.
There has been a conservative effort by some, (as far as I've seen not from the Clinton Campaign). The huge wins in such contests have been marginalized by many Clinton supporters using this very fact.
As a matter of fact, I do see a half truth in this "meme". I believe that there is a growing minority withing the Republican party that hopes for an Obama nomination. But it is not for the reasons promoted my the more militant supporters of Clinton's candidacy.
Many moderate Republicans, disillusioned by the neo-conservative movement that has taken over their party, are humbled by the respect they perceive coming from Obama and his surrogates. They know that Obama doesn't represent their core social and economic ideals, but are willing to overlook this simply because they do not feel as though they are being talked down to.
Considering their options, and how bent over they felt after the Bush administration, an up front honesty from a candidate trumps their other two choices; firebrand disrespect from a Clinton Campaign, or bald-faced liars from any Republican garnering support from the old GOP guard.
This pattern also ring in my ear concerning Clinton and the old Guard GOP and the neo-cons. Now I admit, this is only conjecture, but don't be surprised when the GOP and the Neo-Cons start saying that they wished they had Clinton over Obama. This has already begun in the far reaches of the right-wing.
Coulter and Rush have already said as much, though it was expressed publicly as an anti-Mc Cain sentiment. But if you use the same "math" as those "Obamacan Retractors", it could be said that the outward backslapping of Obama by the likes of Luntz and Buchanan could be an attempt to scare Democrats into the arms of the Clinton camp. Their possible logic would be that a Clinton/DLC administration would be more sympathetic to the neo-conservative wing of the Republican party.
This I do know, their will be no easy path for any Democrat in '08. So before you go into that voting booth, use your head, so that when you get into that booth, you can use your heart.
(on edit I reworded this "though not visible to me, by Clinton's campaign I may have missed something" in paragraph 2 so that it made sense, and would not be misconstruded)
(cross posted at the bottom of some other lost thread on this subject)
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=132x4722435