Acandidate running for office campaigns on the idea of growing the economy, so all americans will prosper. since virtually all americans agree that economic prosperity is a good thing, this candidate's issue is a

The issue taken up by the candidate is a national issue.

Explanation:

For the candidate running for the post of national level authority, it is mandatory to raise and talk about issues that are of national importance. The issues that would only address local and insignificant concerns would not help the candidate secure support from all over the country. The issue of economic growth of the country is primarily of everyone’s concern and is thus bound to fetch everyone’s attention.