Niccolo Machiavelli was the much maligned Renaissance writer who wrote The Prince, an objective, how-to manual for seeking and holding power in 16th Century Italy. His advice when an enemy appears to be divided: Do not attack the enemy, this will unite the bickering factions and unite them against the external enemy (you), instead, give covert support to the weaker faction and reap the rewards after your enemy has exhausted itself with a civil war.
The announced candidacy of Bernie Sanders for the Democratic nomination for the 2016 election of POTUS appears to have a great deal of support from the progressive side of the Democratic Party. This insurgency from the Left may or may not disturb the inevitability of Hillary Clinton. Aside from the upset of 2008, the nomination of a far left candidate is a recipe for defeat for Democrats in the national election; consider the landslide 1972 Nixon vs. McGovern.
I would offer this advice to the G.O.P.: Lavishly and secretly fund a Bernie Sanders campaign with the hopeful result of a bitter division into a centrist party (Clinton) and a progressive third party (Sanders). This could render the same result that put Bubba in power in ’92; the conservative vote was split between Bush the First and the third-party candidate, Perot.
This strategy has considerable risk, and exposure could cause a disastrous backlash. The other ingredient of this strategy would be nominating a candidate that could actually win a national election.