And I'm going with Merriam-Webster sense 2a: excessive or unreasonable enthusiasm.
Are Republicans already dissatisfied with their 2016 field? (Washington Examiner, 7/21/2013)
Excerpt: By all accounts, Ted Cruz, a man who has been in the Senate for all of seven months and was virtually unknown on the national scene just a year ago, dazzled Republicans during a weekend visit to Iowa. That was due first, of course, to Cruz’s considerable appeal as a politician. But the intensity of Cruz-mania could also reflect an emerging Republican unhappiness with the party’s 2016 presidential field.
Shades of Akin and Mourdock on the national level.
Is Ted Cruz eligible under the Constitution to become president?