“What is Vietnam?” is not a question with an easy answer, but The Greatest Beer Run Ever tackles the challenge anyway. Like the plethora of media featuring the country, Peter Farrelly’s film runs headlong into the notion that what is an S-shaped piece of land in Southeast Asia can also be a dream after the Fall of Saigon. Sadly, Beer Run doesn’t do that. Frankly, since the makers of Green Book are at the helm, it must have never felt the need to. Farrelly seems to have deemed nuance the pooper of the party. In this case, the party constitutes the real-life U.S.-to-Vietnam journey of 26-year-old John “Chickie” Donohue (Zac Efron) to give morale-boosting Pabst Blue Ribbon cans to soldiering friends in 1967. And so, in displaying its understanding of Vietnam, the film collectively cycles through “Thailand,” “kumbaya,” “both-sides-ism” and “the motions.” Anything to keep the beer mobile and its delivery enjoyable first. Avoiding the actual issues seems to be the strategy. since they would force the film to form a thoughtful, more profound answer to the question, “What is Vietnam?” It’s too much work, and something Farrelly doesn’t have the skillset, subtlety, and style to address.