Libertarians do not want to leave the borders "wide open". Badnarik on immigration and border security:
http://www.badnarik.org/plans_immigration.php
Libertarians want to use our military to protect our borders. Immigration and border security are two different issues. Most Libertarians want to allow immigration but have heavy border security. Right now, our defenses consist of:
This is unacceptable.
Coupled with open, easy immigration for the peaceful, I advocate a vigorous national defense against our enemies. Terrorists and criminals who attempt to enter the US via a Customs and Immigration station should be denied entry and, where applicable, arrested or extradited. Terrorists and criminals who attempt to enter the US via other points along its 95,000 miles of border and coastline should be treated as what they are: invaders against whom our armed forces must respond. There are obvious exceptions Cuban and Haitian "boat refugees" who don't have much control over where they make landfall, for example but they are exceptions, not the rule.
As a Libertarian, I reject a conception of national defense that keeps American troops overseas, meddling in the affairs of other nations. Instead, I advocate a national defense which, sans any attack which might require retaliation elsewhere, focuses on the logical area: the nation's borders. As president, I would work to eliminate the Border Patrol and treat border issues as what they are: defense issues coming under the mission and scope of the armed forces. In an age where the equivalent of a large invasion force can be packed into a suitcase-sized box containing nuclear, chemical or biological weapons, no lesser response will do.
http://www.badnarik.org/plans_immigration.php
Libertarians want to use our military to protect our borders. Immigration and border security are two different issues. Most Libertarians want to allow immigration but have heavy border security. Right now, our defenses consist of:
This is unacceptable.