There is a lot of noise about immigration, particularly illegal immigration, to the United States of America. Many people are trying to prevent illegal immigration by suggesting that such people should be arrested and deported. A huge wall should be constructed along the Mexican border.
Texan Governor Perry has suggested putting up TV cameras all along the border, broadcasting images to the Internet. Those cameras will end up in pawn shops shortly after they are installed, if they aren't used for target practice.
All of this is short term thinking. Short term thinking just looks at the immediate problem and tries to solve it right now. But illegal immigration is not an immediate problem, it is a long term problem. As such it really needs to be solved with a long term solution.
What is the real cause of illegal immigration? It is jobs and the disparity of wealth between the US and Mexico. We don't have an illegal immigration problem with Canada. Why? Because Canada is, roughly, on an equal economic basis with the US. The result is that some Canadians come down here to work, and some US citizens go up there to work, but there is no need to do it illegally.
Think about what would be a desirable future between the US and Mexico. Would it be an 800 mile long fence between the countries? Would it be armed guards along the border? Or would the best future be an open border that people can cross freely, either way, whenever it was something they wanted.
We have such a border with Canada, but even more specifically, we have such borders within the US. People from West Virginia can move to California whenever they want. People can freely cross the border from Georgia into Florida, or from Oklahoma into Texas. Such movements cause local disruptions -- all the Okies moving to California during the Dust Bowl, African-Americans moving from the South to Chicago, the freezing residents of the Rust Belt moving South to the warmer climates of Florida, Arizona and Texas to retire -- but we don't respond by building fences along the northern borders of these states; we look for ways to make it work.
Now, I personally don't understand why people stay in places like West Virginia or North Dakota or Utah when there are much better places available, but they do. And if you want people to move to North Dakota (and stay there), you try to find out what people want and make it available there.
Similarly, we need to work with Mexico to make Mexico a place where people want to stay. This means raising the economy, raising education levels, and making it a place where people, Mexicans and Americans, want to stay. Giving people, in Mexico, a good alternative to packing up and moving to the US.
That is the only workable long-term solution.
Given that, we need to determine how best to achieve that long-term goal, and select our short-term goals to help us get to our long-term goal.