U.S. Secretary of State John Kerry, left, speaks during a joint news conference with Ukrainian Prime Minister Arseniy Yatsenyuk, in Kiev, Thursday, Feb. 5, 2015. (Sergei Chuzavkov/AP)

Niccolo Machiavelli, perhaps the shrewdest political philosopher in history, believed that great events were shaped by luck — or “fortuna,” as he called this unpredictable force of life. The same actions might produce success or failure, depending on the whims of the goddess Fortuna.

You wouldn’t know it by listening to gloomy commentators, but the United States has been extremely lucky of late. Its inherent economic strength has become more obvious. Meanwhile, its adversaries have suffered reversals — some of their own making, others because of bad luck.

With this advantageous position, the United States can afford to think like a superpower. It shouldn’t rush to make concessions to weaker nations or to gain agreements that aren’t fully ripe, as may be the case with nuclear talks with Iran. It shouldn’t be shy about helping its friends or making its adversaries pay for their reckless behavior, as in dealing with Russia’s aggression in Ukraine.

It’s a diabolical piece of luck, too, that the Islamic State, which poses a deadly threat in Syria and Iraq, has taken the hideous action of burning alive a Jordanian Muslim pilot. Millions of Arabs are outraged and calling for revenge. With this death-cult action, the extremists have done more to undermine their standing than a thousand U.S. bombing raids or a million State Department propaganda tweets could have accomplished.

Americans are always asking why Arabs don’t denounce atrocities committed in the name of Islam. Well, it’s happening now. “Barbarity,” screams the headline in the London-based Arabic newspaper Al-Hayat. “Vicious,” says the emir of Kuwait. A “brutal, heinous crime,” says Saudi Arabia. The United States shouldn’t raise its voice louder than the indignant Muslim world. Restrain the rhetoric; use force invisibly; act like a superpower.

To understand the current “correlation of forces,” as the Russians like to say, let’s look at some evidence about American economic power gathered by Goldman Sachs last month in a report titled “U.S. Preeminence.”

First, GDP growth: From the peak before the 2008 financial crisis, the U.S. economy has grown a further 8.1 percent in real terms, compared with declines of 2.2 percent for the euro zone and 1.1 percent for Japan. The gap between GDP growth rates in fast-rising emerging-market economies and the United States shrank from 6.5 percentage points in 2007 to 2.6 points in 2014, and it’s expected to narrow further this year to 1.2 points as China slows.

When you look at business statistics, the gains are even more striking. The debt leverage of listed U.S. companies is lower than that of firms in any of its trading partners. U.S. labor productivity is substantially higher than that in the euro zone, Japan or any emerging-market country. In average manufacturing costs, the United States has an advantage over every one of the 10 largest exporters except China.

Finally, there’s the remarkable growth in U.S. energy production. Last year, the United States surpassed Saudi Arabia to become the top oil and gas producer in the world, six years earlier than analysts had expected. Some of the incentive for producing shale oil and gas has declined, as oil prices have fallen about 50 percent from their peak last July. But that’s great news for U.S. consumers.

Powerful countries such as the United States have the wind at their back. They don’t need to rush things in the clamor of partisan politics and 24-hour news cycles. That’s why I hope the Obama administration won’t make too many concessions to Iran in its eagerness to reach a nuclear deal. If the Iranians are truly ready to turn away from confrontation and verifiably unplug their nuclear program, fine. If not, let’s wait. In a world of low oil prices and an Iranian population desperate to end its isolation, time doesn’t favor the Iranian hard-liners.

On Ukraine, a powerful United States has been wise to leave open the exit ramp for a reckless Russian President Vladimir Putin — and to accept the idea of a Ukraine that would accommodate Russian and Western interests. This effort continued Thursday in Kiev. But if Putin foolishly spurns compromise and continues his proxy war in eastern Ukraine, the United States should provide limited arms to Kiev, as argued this week in a report by experts from the Atlantic Council, the Brookings Institution and the Chicago Council on Global Affairs. If Putin escalates further, at a time when Russia is weakened by low oil prices, he faces a ruinous war across Ukraine. His decision, not ours.

Fortune blesses strong nations, but only when they act with resolve. Squandering America’s real advantage to gain short-term diplomatic success would be a big mistake.

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