Answer:
That statement is false.
Explanation:
Grand Strategy is a plan that members of each party used as some sort of ideal on how they will organized the country's resources.
Its true that the majority of Republican party and Democratic party support a specific grand strategy, but some members of each party actually might disagree with the majority.
For example,
Republican party tend to support higher military spending as their grand strategy, while the Democratic party rend to the reduction in military spending. But Hillary Clinton also support high military spending even though she has an affiliation to Democratic party.
