“There are at least three sectors of the border, one in particular, that are just completely insecure.”

— Marco Rubio on Friday, February 27th, 2015 in a speech at CPAC

Sen. Marco Rubio said he’s learned some lessons from his first failed foray into the immigration policy game.

“What I’ve learned, is you can’t even have a conversation about that until people believe and know — not just believe, but it’s proven to them — that future illegal immigration will controlled,” Rubio said. “That is the single biggest lesson of the last two years.”

Rubio gave this stat in a recent CPAC speech: “There are at least three sectors of the border, one in particular, that are just completely insecure.”

The southwest border spans from San Diego to the southern tip of Texas, and it is broken into nine sectors. Are at least three of those sectors “completely insecure”? We decided to check.

Border patrol agents have many duties including: Stopping illegal immigration, preventing gun and drug smuggling, thwarting terrorist plots.

There’s no set definition for what constitutes a “secure” border, experts told us. If you think one failure to apprehend a border crosser means a sector is insecure, then the whole border lacks security. But where do you draw the line for what constitutes “secure.”

Additionally, we don’t know exactly what percentage of people successfully cross the border, nor how many successful drug running missions there are each year, etc. We can measure how many are caught, but that’s only part of the equation. When Rubio says the border is “completely insecure,” that’s not really grounded in any set metric.

We asked Rubio’s office to explain what he meant by “completely insecure” and which three border sectors he was referring to. Spokeswoman Brooke Sammon did not respond to our multiple emails and calls.

A Government Accountability Office report from 2011 on border control measures broke down how much of each sector in 2010 was under “operational control.”

That means agents had the ability to apprehend violators upon or immediately after entry.

Here’s what they found.

Four sectors obviously stick out for their lack of operational control: Big Bend, Del Rio, Laredo and Rio Grande Valley. All four achieved operational control for less than 40 percent of their respective sector.

Again, this data is from 2010, so it’s unclear how those sectors of the border have fared since. At the time, operational control of the border had been increasing by 126 miles annually dating back to 2005 and more resources have been put toward the border since.

Also, the Department of Homeland Security scrapped those assessments because they don’t provide much useful information for determining the effectiveness of border security in a particular sector. It hasn’t replaced it with anything more useful yet, said Theresa Brown, director of immigration policy at the Bipartisan Policy Institute.

There are two sectors that are well below the rest in effectiveness ratings: Big Bend and Rio Grande.

Experts we spoke with easily identified the one border sector Rubio singled out when he said “one in particular” faced security issues: the Rio Grande sector.

The number of apprehensions at the Rio Grande sector doubled to 256,000 in 2014 as a wave of unaccompanied minors and migrants from Central America attempted to enter the United States through the southernmost part of Texas. This has posed new challenges for the sector, which also saw a 7 percentage point drop in its effectiveness rate from 2012 to 2013.

“I’m not sure what the senator means when he says ‘completely insecure,’ but it is true that there has been a big surge in border crossers at that point over the last few years,” said Alex Nowrasteh, immigration policy analyst at the libertarian Cato Institute.

As for the other two sectors that are “completely insecure,” experts studying immigration at four different think tanks of varying political stripe couldn’t guess which two Rubio was referring to.

The border sector with the most activity other than the Rio Grande is Tucson, which for a long time was the preferred route for Mexican immigration. However, apprehensions are down there from over 600,000 in 2000 to less than 90,000 in 2014.

Rubio’s statement in general misses the broader trends across most of the border: Illegal migration through the border is down considerably from the record highs of the previous decade.

In 2007, there were 1.6 million apprehensions, turn backs or gotaways at the border, according to the Bipartisan Policy Center. That dropped to 741,881 in 2013.

Additionally, eight sectors, including the troubled Rio Grande, had higher effectiveness ratings in 2013 than they did in 2006.

“The number of people trying to come across the southwest border is substantially lower than it was in the late 1990s and early 2000s,” Brown said.

Our ruling

Rubio said, “There are at least three sectors of the border, one in particular, that are just completely insecure.”

We don’t know how Rubio came up with three sectors, and neither did experts we spoke with. There certainly is one sector of late with a troubling amount of activity, the Rio Grande in south Texas, that also is less effective at apprehending border crossers than other sectors.

The number of people attempting to cross the border is down everywhere else, and the effectiveness rating is up in eight of nine sectors since 2006.

We rate Rubio’s statement Mostly False.