Europe appears on the brink of another recession. Islamic militants have seized Iraqi territory. Russian troops have massed on the Ukraine border, and the resulting sanctions are disrupting trade. An Ebola outbreak in Africa and Israel's war in Gaza are contributing to the gloom.

It's been a grim summer in much of the world. Yet investors in the United States have largely shrugged it off - so far at least.

A big reason is that five years after the Great Recession officially ended, the U.S. economy is showing a strength and durability that other major nations can only envy. Thanks in part to the Federal Reserve's ultra-low interest rates, employers have ramped up hiring, factories have boosted production and businesses have been making money.

All of this has cushioned the U.S. economy from the economic damage abroad. And investors have responded by keeping U.S. stocks near all-time highs. Not even reports Friday of a Ukrainian attack on Russian military vehicles unnerved investors for long, with blue-chip stocks regaining nearly all their midday losses by the close.

"We're in a much better place psychologically," says Mark Zandi, chief economist at Moody's Analytics. "And it's allowing us to weather the geopolitical threats much more gracefully."

Still, the global turmoil comes at a delicate time.

It might not take much - an oil-price spike, a prolonged recession in Europe, a plunge in business or consumer confidence - to derail the global economy.

Here's a look at the strengths and weaknesses of the U.S economy:

Strengths

More jobs: Hiring in the United States has surged in the first seven months of this year.

Monthly job gains are averaging a solid and steady 230,000, based on government figures. That's roughly an average of 35,000 more jobs each month compared with last year.

Fewer people are applying for unemployment benefits. And fewer new hires are working as temps. Both trends suggest stronger job security.

Economists say the cumulative effect of all those additional paychecks should propel growth and help insulate the U.S. economy from trouble abroad.

Record profits: Earnings at companies in the Standard and Poor's 500 index are on track to jump 10 percent in the second quarter from a year earlier, according to S&P Capital IQ, a research firm. That would be the biggest quarterly gain in nearly three years.

That news has helped the S&P 500 index climb nearly 6 percent this year, extending a bull market into its sixth year. The gains have been remarkably steady, too. The stock market hasn't suffered a "correction" - a drop of 10 percent - in nearly three years, twice as long as is typical.

Still, some markets outside the U.S. are falling.

Japan's benchmark Nikkei 225 is down 6 percent this year. Germany's DAX has lost nearly 5 percent, and France's CAC 40 is down 3 percent.

At the same time, global investors have been pouring money into U.S. Treasurys, long seen as a safe bet in troubled times.

Christine Short, a director at S&P Capital IQ, worries that more grim news from abroad could send U.S. stocks tumbling. "Markets are ripe for correction," she says. "The only question is, What is the catalyst?"

Threats

Foreign exposure: Though the U.S. economy has managed so far to withstand the economic and geopolitical turmoil abroad, it isn't immune to it.

Where are the shoppers?: Retail sales stalled in the United States last month. Wage growth has failed to surpass inflation, leaving many consumers unwilling or unable to spend more. Sales at auto dealers and department stores fell in July.

"Consumers are finding they can live without a lot of the stuff they used to buy automatically," says Joel Naroff, president of Naroff Economic Advisors, in a research note. "Right now, people are just not parting with their hard-earned funds."

Oil spike: Will fighting in Iraq and Ukraine upend global energy markets, and raise the cost of filling your gas tank and heating your home?

Europe is worried because it gets much of its natural gas from Russia. And Iraq is the second-biggest OPEC oil producer. Before dropping last month, crude oil prices hit a 10-month high in June on news of victories by Islamic State fighters.