After being sworn in, newly confirmed U.S. Attorney General Jeff Sessions told Americans he was concerned about rising violent crime rates — what he called a "dangerous trend."

The comments sounded a lot like those made by Sessions' boss, President Trump, who promised to end "American carnage" during his inauguration speech last month and throughout his campaign repeatedly warned about a surge in violence.

But law enforcement data show these crimes have been on a steep decline since the 1990s and have hit their lowest points in decades.

Both of these cannot be true. Either violent crime is rising or falling. And the answer matters. Both Sessions and Trump wield great power in driving the national conversation and influencing criminal justice policy.

These policies come at great cost to the taxpayers — the war on drugs is estimated to have cost more than $1 trillion — and the only way to effectively combat threats to the nation come from fact-based policies, said Ames Grawert, who studies crime trends as counsel for the Brennan Center for Justice in New York.

"If you start with bad facts, you're going to get bad policies that might make the country less safe, that might strain relationships further between police and communities of color, that send more people to prison for little reason," Grawert said.

So let's explore: Despite everything written to the contrary, could Sessions and Trump be right?

In Minnesota, according to the FBI's Uniform Crime Reports, rates for violent crimes like murders, robberies, rapes and aggravated assaults rose in the 1980s and peaked near the mid-1990s — commonly known as the "Murderapolis" years in the Twin Cities. Violent crime spiked again in the mid-2000s and has been in decline through 2015.

There appears to be a slight increase in rape and murder from 2014 to 2015, but these rates still are very low compared to the '90s. And a one-year bump isn't enough to make a trend.

Nationally, according to the Uniform Crime Report statistics, violent crime in the U.S. peaked in the early 1990s. The data reflect a significant drop in all violent crime — with a few years of fluctuation, particularly in the mid-2000s — all the way until 2015. There is some mystery on what exactly accounts for the decline, though most credit it to statistics-based crime fighting tools like CompStat, the growth of income and a trend toward decreased drinking.

There were, however, some increases in violent crimes from 2014 to 2015 — and these aren't insignificant.

The murder rate, for example, saw the largest increase in more than 47 years — a statistic that Trump falsely interpreted as a 47-year high. But the short-term jump is not nearly enough to reverse a trend that has been decades in the making and it does not support the comments made by Sessions and Trump. In fact, even with the increase, the murder rate is not half of what it was in 1980.

Of course, there are exceptions. Trump has called Chicago out by name — even threatened to send in the feds — because of the city's reputation for violent crime. The federal data show the murder and assault rates in Chicago have indeed gone up in the past couple of years, and a new analysis from the Economist suggests it continued to rise in 2016.

Yet even with this increase, murder and assault rates still are lower than in the '90s. Other violent crimes, like robberies, were down in Chicago. And criminal justice experts point out that an increase in one city doesn't amount to a national trend.

"Not every city is Chicago," said Grawert of the Brennan Center. "The experience of these few cities is just not the experience of the country as a whole."

So this brings us back to our original question: What are Sessions and Trump talking about when they say violent crime is rising?

Grawert says the comments are plainly false, and he has a theory as to why they were made. He believes the Trump administration is purposely overstating the problem of violent crime in America to generate support for policies like the border wall and the travel ban.

"They only make sense as an overreaction to a clear-and-present danger," he said. "So I think he needs to make the country feel less safe … to sell some of these policies."

We asked Attorney General Jeff Sessions' media office to clarify these comments or provide an alternative data source, but we did not receive a response.