Donald Trump is entitled to his own opinions, not his own facts, to paraphrase Daniel Patrick Moynihan.

Trump gets a lot wrong in his comments about immigration and Mexico. There is no evidence that Mexican officials are dispatching criminals across a porous border, and immigrants don't commit more crimes, studies show.

Yet even some of the Republican presidential candidate's critics nonetheless give him credit for tapping into something real: the perils of President Obama's lax approach to immigration, generally, and enforcement along the Mexican border in particular.

"We need to secure the border," says Carly Fiorina, another presidential contender.

This, too, is misleading.

"The border is more secure than it has been in years," says Marc Rosenblum of the Migration Policy Institute, an independent research organization that collects and analyzes immigration data.

Consider:

• Net migration from Mexico is negative, many experts say; more people are returning to Mexico than are illegally crossing the border into the U.S.

• There are 11 million undocumented immigrants in the U.S., down from more than 12 million in 2007. The downward trend began in the final year of the George W. Bush administration.

• More undocumented immigrants have been deported under Obama than under any other president. This number is down now, after complaints from pro-immigration groups that the policy was too zealous and the president's administrative actions exempting millions from deportation.

• Spending on immigration enforcement exceeded $18 billion last year, almost twice as much as a decade earlier. The U.S. spends more money on controlling the border than on all other federal criminal law enforcement efforts combined.

• Apprehensions, a good guide to crossings, are down considerably along the frontier with Mexico, according to the Border Patrol. Independent studies by Princeton University and the University of California, San Diego, buttress this notion. "Apprehensions of Mexicans are lower than any time since 1970," says Jeffrey Passel, a senior demographer at the Pew Research Center.

• Most seeking illegal entry to the U.S. enlist smugglers to make the journey. The average fee has soared to more than $3,000, a 50 percent increase compared with a decade ago that reflects the increased difficulty of the crossing, analysts say.

These numbers are no secret. Yet they rarely enter the public debate. Democrats often avoid the issue and Republicans sound the alarm about a huge crisis on the border.

The situation certainly isn't perfect. The Border Patrol estimates that the U.S. has about 80 percent security. Some critics demand 100 percent.

That's an unrealistic goal, Michael Chertoff, secretary of homeland security under Bush, recently said at a conference, adding that such a demand would be unnecessary from a budgetary and efficiency perspective.

The Berlin Wall, fortified with trigger-happy armed guards, had about a 95 percent secure control.

There are calls to build a wall along the 1,989-mile border with Mexico. There are robust fences along about one-third of its length now. Former New Mexico Governor Bill Richardson once said that if a 12-foot wall were erected, there would be "a lot of 13-foot ladders."

There are other causes for the changes, including economic conditions in the U.S. and Central America and a much lower fertility rate in Mexico. But analysts credit tougher and better border enforcement and pressure on the Mexican government as important factors in the improvement.

One way to get better than 80 percent security would be to pass the 2013 bipartisan immigration bill, which cleared the Senate and stalled in the House. Along with a pathway to citizenship for undocumented workers, it placed huge emphasis on border enforcement, authorizing an additional $46 billion to double the number of agents and investing billions in the most high-tech surveillance.

But among Republican presidential candidates, Chris Christie, Scott Walker and Marco Rubio have flipped on their support for the bill — citing the pathway issue — and Jeb Bush has waffled. Only Lindsey Graham supports this measure that would further stem illegal entries.

It's easier politics to rail against the invading Mexican bandits.