it would be a rather Rovian move.
In NH, the large cadre of Indy voters would sometimes urge their fellows to vote up the weakest candidate in the opposing camp, just to give their eventual pick an easier target. That was the idea, anyway. Background:
The merits of open versus closed primaries have been widely debated. Proponents of open primaries argue that voters should be able to choose which primary they will vote in at each election. Open primaries allow participation by independents unwilling to declare a party affiliation to vote and prevent intimidation of voters who wish to keep their affiliation private. Party organizations prefer closed primaries because they promote party unity and keep those with no allegiance to the party from influencing its choice, as happens in crossover voting, when members of rival parties vote for the weakest candidate in the opposition's primary. Several states have adopted variations, including the mixed primary, which allows independents to vote in either party's primary but requires voters registered with a political party to vote in their own party's primary. Following legal challenges (particularly by the Democratic and Republican parties), some variations, such as Washington's blanket primary, which enabled voters to select one candidate per office irrespective of party affiliation, and California's so-called “jungle primary” (a variation of the blanket primary), in which voters chose one candidate per office but only the votes of registered party voters were counted in determining the winner of each party's primary contest, were declared unconstitutional in the early 21st century.
http://www.britannica.com/presidents/article-9061375