No. It is not a primary, it is a caucus. That means that Republicans choose, not Democrats or independents.
Democrats and independents can switch their registration, of course, in order to participate, but would you really want to prevent that? Some of them are fed up with Obama.
The Dems who don’t like Obama can vote against him in the general election. In the meantime, I don’t want Democrats eliminating Republican first choices in the primaries (or “caucuses”).