Global Firepower Index GraphicSkye Gould/Business Insider

Here are key findings from the index:

America’s Investment In Being The World’s Police Force

The United States clearly leads the world in military spending at more than $6 billion. China is the closest nation to follow the US at nearly $130 billion — which is still less than a third of America’s overall spending.

According to a report from the Stockholm International Peace Research Institute (SIPRI), the US has reduced its defense budget by 7.8% chiefly due to America’s gradual withdrawal in overseas military operations, like Afghanistan and Iraq.

Meanwhile, Russia has increased its arms spending by $88 billion and plans to ‘modernize’ its current weapons arsenal.

The Role Of Aircraft Carriers

Aircraft carriers contribute greatly to a country’s overall military strength. These massive vessels allow nations to project their force far beyond their borders and across the entire face of the globe by functioning as essentially a mobile naval and air force base. Aircraft carriers can also carry drones, significantly changing the global surveillance game.

The U.S.’s absolute monopoly on these vessels significantly boosts the country’s forward operating power. The U.S. has deployed an aircraft carrier towards the Persian Gulf to bolster its sea and air power before possible strikes against ISIS in Iraq. Russia has previously deployed an aircraft carrier to the Mediterranean to display its seriousness in propping up Assad in Syria.

North Korea’s Submarines

An anomaly in the Global Firepower index is North Korea’s ranking as a world leader for submarines. North Korea’s submarine lead is due to the fact that the country, in terms of pure numbers, has more submarines than any country in the world.

However, these submarine are almost entirely unusable. A third of North Korea’s subs are noisy diesel powered Romeos, which have been obsolete since 1961. These submarines have a weapon’s range of only four miles, whereas a modern U.S. submarine has a weapon’s range of 150 miles. By and large, this fleet is unsophisticated but durable, according to the U.S. Department of Defense.

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