If the Arizona border-patrol militia doesn't scare you yet, it should: The Constitution calls for a "well-regulated militia", not volunteers showing up against the advice of the Border Patrol.
Some of the unintended consequences of a volunteer militia showing up uninvited:
- They're disrupting the Border Patrol's normal monitoring operations by setting off sensors and making the cameras harder to use
- They're drawing the favor of white-supremacist groups -- whether or not they want the endorsement
- They're annoying the neighbors and legitimate residents of the area
- They're only shifting the problem to nearby areas instead of actually stopping illegal immigration
- They're hurting small businesses that rely on customers who are legal immigrants, but who have been frightened off by the militia groups
- Doing so reduces the rewards for criminals to smuggle immigrants across the border illegally. The easier it is to do anything legally, the less incentive there is to offer a competing service illegally. How many people would become ticket scalpers at ballgames if there were more seats available in the stadium at lower prices?
- Easier immigration rules allow temporary immigrants to return home sooner. If it takes, suppose, $5000 to cross the border illegally, then someone who's working in another country just to save up some money then return home has to earn an additional $5000 to cover his or her costs. That means a longer illegal stay in the other country. If it's easier to cross the border, especially on a temporary basis, he or she's likely to go home much sooner -- $5000 worth of work sooner.
- The security problem is not immigration per se, but the risk that terrorists will use established means of illegal immigration to cross the border undetected. The more traffic that is routed through official, sanctioned, and monitored channels (i.e., legal immigration), the more effective efforts at controlling illegal immigration can be.