WASHINGTON — Freshman GOP Sen. Tom Cotton says the United States must show it will start a war to prevent one, and suggests the country might need to spend nearly $900 billion annually on its military.

The Arkansas lawmaker, who in January moved from the House to the Senate, told an audience on Capitol Hill that the US is in a similar position as in the 1930s, when Adolf Hitler rose to power in Germany.

And, for Cotton, the Islamic State group, Iran and Russia are public enemies one, two and three.

"Iran is only growing more bold and more aggressive," Cotton said, adding that Washington under President Barack Obama has "withdrawn from the world."

Cotton, an Army veteran, claims Iran now "dominates or controls five capitals" in the Middle East "in its drive for regional hegemony." What's more, he says Tehran has improved its ballistic missile fleet "without the [nuclear] bomb."

"Imagine Iran with the bomb," Cotton said."You don't have to imagine much, just look at North Korea."

Cotton was the author of a controversial letter to Iranian officials threatening a GOP rejection of the reported parameters of a deal Iran is pursuing with the US and four other global powers over its nuclear program.

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Meantime, Cotton says America's military is in decline. The percentage of US gross domestic product that is spent on the military is "paltry," he said.

He noted Washington spent around 5 percent of its GDP on defense during the Reagan administration. That would translate to about $885 billion today, and Cotton believes the country can afford it.

Such spending is needed, he said, because the US military — and a willingness by presidents to use it for "war" — is the lone guarantor of global stability.

Cotton said no single amount can be pinpointed for what level of military spending is really needed.