Of course, if Iran develops a nuclear weapon, or even a nuclear-weapons capacity, its power will grow. But it will still face neighbors—Israel, Pakistan, India—with larger nuclear arsenals of their own. And there is no reason to believe that Tehran will commit regime suicide by using a nuclear weapon against Israel or anyone else, and thus invite a massive nuclear response, given that it has proved emphatically non-suicidal during its 36 years in power.

China, by contrast, is not a midsize power. It’s a superpower. At current prices, its GDP is 28 times larger than Iran’s. Its military budget is roughly 13 times larger. Its willingness to invest vast sums in the economic development of other nations gives it tremendous soft power. And it is claiming much of the South China Sea as its own, thus asserting dominion over a territory with vast oil and gas reserves through which one-third of the world’s shipping travels.

From 1941 to 1989, the United States risked war to prevent great powers from dominating the world’s economic and industrial heartlands, and thus gaining veto power over America’s ability to conduct international commerce. That’s what China is seeking today.

So why aren’t Lindsey Graham and his GOP presidential competitors talking more about China? (To be fair, Hillary Clinton isn’t talking much about China either. But her campaign thus far has been much less weighted toward foreign policy in general.)

Three reasons come to mind.

The first is that the Chinese threat isn’t visually spectacular. What made ISIS a household name in the United States last year, even more than the group’s territorial gains, were its gruesome murders, especially of Westerners. The horrific images of those killings, broadcast endlessly on television, bred a primal fear that Washington politicians were quick to exploit. Those politicians pressured the Obama administration to begin its bombing campaign in Iraq and Syria, which gave the story even more juice because the United States was now at war.

Via the catchall of “radical Islam,” American politicians have transferred some of the anxiety sparked by ISIS to Iran: Today they have butcher’s knives; tomorrow, nukes! By contrast, China’s incremental moves to build islands in the South China Sea or even ram the occasional Filipino fishing boat produce far less drama. No matter how serious a challenge they pose to America’s role in the Pacific, they don’t appear to threaten American lives. And they won’t—until a confrontation between the Chinese and American militaries, in disputed ocean or airspace, raises the prospect of war. Until that happens, China’s challenge will remain on Page A17 of the newspaper.

The second reason presidential candidates devote so much more attention to “radical Islam” than to China is money. There’s no conspiracy here. Sheldon Adelson, who along with the Koch brothers is the most influential donor in today’s GOP, proudly acknowledges that, for him, Israel’s “security”—and thus, Iran’s nuclear program—is issue number one. And there are mini-Adelsons backing all the leading Republican candidates who talk tough on Iran. China hawks, by contrast, are far harder to find in the GOP donor class. In fact, given the stake many financial and corporate types have in U.S.-Chinese economic ties, it’s not clear that GOP donors even want GOP presidential candidates to take a hard line against Beijing.