Illegal immigration continues to decline, reaches 13-year low

The Arizona-Mexico border fence near Naco, Arizona, March 29, 2013.
The Arizona-Mexico border fence near Naco, Arizona, March 29, 2013.
At the most recent Republican presidential debate, Donald Trump recited familiar concerns about immigration, which has helped propel him to the front of the pack. "We have no borders.... Illegal immigration is beyond belief," the GOP frontrunner said. He added, "I'm tired of seeing what's going on, between the border where the people flow over; people come in; they live; they shoot."
That's probably a decent summary of how many Republican voters see the problem of illegal immigration. Imagine how surprised they'd be if they considered the real-world evidence. The L.A. Times reported overnight:

The number of immigrants living in the U.S. illegally is at its lowest in more than a decade and, for the first time in years, has probably dropped below 11 million. A new study by the Center for Migration Studies estimates that 10.9 million immigrants are living in the country without authorization. That is the lowest level since 2003 and the first time the number has dipped below 11 million since 2004.

The study is available in its entirety here.
A Washington Post report on the findings explained, "The number of undocumented immigrants has fallen each year since 2008, the report says, driven primarily by a steady decline in illegal migrants from Mexico." The article added that the evidence "could impact the fiery debate over immigration unfolding on the campaign trail."
Well, I suppose it could.
Kevin Appleby, the Center for Migration Studies' senior director of international migration policy, told reporters yesterday, "The facts of the report tell a different story than what you might hear on the campaign trail or in the halls of Congress, where many send a message that we're being overrun by undocumented immigrants. The facts and the data show that's just not true. Hopefully, political discourse will be more fact-based going forward."
Let's go ahead and start lowering expectations now.
Look, I'd be delighted if facts had a powerful effect on our political debates, especially during the presidential campaign, but Republican voters believe President Obama has increased the deficit, given Iran permission to build a nuclear weapon, abandoned border security, proposed widespread gun confiscation, and imposed socialized medicine on the country -- none of which is even remotely true.
It's hard to be optimistic about the introduction of new facts shaping the debate in any meaningful way when one of the major parties and its national candidates don't even believe in climate change.
Illegal immigration has declined in the United States in every year of the Obama era. How many GOP candidates would acknowledge such a detail? How loud would the booing be if they did?