The latest issue of Bloomberg Businessweek highlights an important issue that has attracted little attention to date in the 2016 presidential race: China.

It doesn’t rival Islamic State or abortion as an issue in the presidential race, but China might be the most complex challenge the winner will have to deal with.

The country, which has the world’s second-biggest economy and second-highest military spending, is a frenemy of the first order. It finances America’s federal budget deficit by buying Treasury bonds, and it sends more students to the U.S. than any other nation. It’s a natural ally on some issues (Islamic terrorism) but an implacable foe on others (freedom of navigation in the South China Sea). …

… China is a litmus test for how the presidential candidates would govern on a broad range of issues. Are they isolationists or interventionists? Do they see foreign policy as a job for the White House or for Congress? How would they strike a balance between concern for human rights and the economy? Which constituency do they most aim to please—business, labor, religious groups, environmentalists, defense hawks? …

… The question of how to respond to China’s displays of military strength offers a clearer picture of what the candidates are about than their grandstanding on what to do in the Middle East. Chris Christie, Fiorina, and Rubio have taken a neoconservative tack on foreign policy, indicating they’d be more willing than others to use force to defend American interests and promote Western democratic ideals in Asia as well as in the Middle East. John Kasich, who declared war on Pentagon waste while in Congress, has nonetheless favored military spending to counter China. Ben Carson hasn’t had much to say about China as a strategic threat at all, except to suggest it’s played a part in Syria’s civil war.

Rand Paul, a libertarian, is leery of foreign entanglements. In Syria he opposes a no-fly zone that could put the U.S. in direct conflict with Russia. On China, he’s adamant that the U.S. should avoid responding to its shows of strength with a big military buildup. That veers fairly close to the policy advocated by Sanders, who focuses on jobs and little else when it comes to China. His spin is that “billionaires” are shipping jobs from the U.S. to China to take advantage of lower wages, at the expense of workers in both countries.