A surge in migrant traffic across the Southwest border into Texas has resulted in a milestone: the front line of the battle against illegal crossings from Mexico has shifted for the first time in over a decade away from Arizona to the Rio Grande Valley of South Texas. …

The increase in Texas is taking place even as the Obama administration says it has achieved unprecedented control over the border with Mexico. The administration, President Obama said last week, has “put border security in place,” with illegal crossings “near their lowest level in decades.”

Apprehensions at the Mexican border — the single best indicator of illegal traffic — are still far below their peak: there were 356,873 last year, compared with 1.6 million in 2000.

But after nearly a decade of steady declines, the count has started to rise again over the past year, driven by the rise in the southern tip of Texas, where the numbers so far this fiscal year are up 55 percent. Since October, 94,305 individuals have been apprehended in the Rio Grande Valley alone, topping the count in Tucson for the first time since 1993.