Which type of election allows only registered members of a political party to vote in that party's primary?

Southern elites might have desired a central military to protect them from ____________________

Fill in the blank(s) with correct word

Based on Downs's issue-attention cycle, what is one reason that policy issues fade from public attention?

a. The problem has no known solution. b. Congress blocks action on the policy proposal. c. People realize that solving the problem will be costly. d. The policy is enacted, and people believe that nothing more can be done.