The Washington Post | Max Boot: The premise behind President Trump�s �America First� foreign policy is that the United States is so powerful that it can achieve its objectives simply by flexing its muscles � and that previous presidents failed to do so because they were globalists and losers. Some analysts sympathetic to Trump think that this premise has been vindicated. As one writer recently put it in the Wall Street Journal: �The past few years have witnessed a marked increase in American power. Washington�s reach is expanding, its ability to enforce its will on others has grown, and it has become more willing and able to use its power disruptively.�

Au contraire. Trump�s confrontations with Iran and China show the sharp limits of what American unilateralism can achieve. Trump has demonstrated he can blow things up, but (ironically for a professional developer) he hasn�t shown any ability to build anything better.

To be sure, the sanctions that Trump imposed on Iran after exiting the nuclear deal � in spite of Iran�s compliance with its terms � have inflicted real pain on the Iranian economy. The International Monetary Fund estimates that Iran�s economy contracted by 3.9 percent in 2018.

Yet despite the best U.S. efforts, Iran continues to sell its oil abroad. The New York Times reported, based on the work of ship-tracking services, that since May, 12 tankers have offloaded Iranian oil in China and the eastern Mediterranean � most likely Syria or Turkey.

Iranian oil exports have been cut from 2.5 million barrels a day in April 2018 to 500,000 a day in June. But even the lower figure appears sufficient to maintain Iran�s aggressive policy across Middle East. Hopes that the sanctions squeeze would cause Iran to cut off its regional proxies, such as Hezbollah and the Houthis, have so far not been realized. The Wall Street Journal reports that Iran�s Islamic Revolutionary Guard Corps �is maintaining support for armed groups in the Middle East and finding new sources of funding, defying U.S. efforts to curb its activities abroad.�

Instead of giving in, Iran is lashing out, thereby raising the risk of war. It is enriching more uranium, it is suspected of attacking oil tankers (Tehran denies responsibility), and it has seized three foreign oil tankers. In response, the Trump administration tried to enlist allies to escort tankers, but it has found that the Europeans, who opposed the U.S. withdrawal from the nuclear accord, aren�t willing to go along. A Politico article on the administration�s futile attempts to marshal allies against Iran is aptly headlined �Trump�s coalition of one.�

Trump�s hope is that sanctions will force the mullahs to come to the table. So far it hasn�t happened. After Iranian Foreign Minister Mohammad Javad Zarif rejected an invitation to come to the White House for talks, the administration petulantly imposed personal sanctions on Zarif. This is a declaration of strategic bankruptcy. The administration has failed and doesn�t know what to do next.

The same is true with China. Trump has already imposed tariffs on $250 billion worth of goods imported from China and now says he will impose tariffs on an additional $300 billion worth of imports on Sept. 1. This pressure has been enough to hurt China�s economic growth and to bring Beijing to the negotiating table � but not enough to extract any meaningful concessions.

Like Iran, China is fighting back. It has already imposed sanctions on $110 billion of U.S. goods, thereby inflicting real pain on U.S. agriculture and forcing Trump to subsidize our �Great Patriot Farmers� (an appropriately Stalinist catchphrase for a socialist policy). On Monday, China rocked the global financial system by announcing that it would stop making further purchases of U.S. agricultural goods and devalue its currency in response to Trump�s �unilateralism and trade protectionism.� The administration responded by declaring China a currency manipulator. Now what?

�The administration has fired almost every salvo it has to force the Chinese into submission,� my Council on Foreign Relations colleague Edward Alden writes in Foreign Policy, �and the two countries are further away from a trade deal than ever before.� Instead of the quick victory he imagined (�trade wars are good, and easy to win�), Trump has blundered into a long-term conflict that holds back U.S. growth and spooks the stock market. The trade deficit � the whole rationale for his trade war � is expanding, not shrinking. The only obvious way out is for Trump to surrender and call it a victory, which may well happen if the trade war threatens his reelection.

So it turns out that it wasn�t a lack of will, or a lack of loyalty to the United States, that kept previous presidents from simply extorting massive concessions from other countries with unilateral action. Trump�s predecessors knew something he doesn�t: The United States isn�t omnipotent, and while allies can be a pain in the neck, we act far more effectively with them than without them.