As part of the current immigration bill now making its way through Congress, the GOP has proposed to double the number of guards at the U.S.-Mexico border to 40,000 and also finish the construction of the remaining 700 miles of fence sitting on the border. This would indeed improve security and keep people from crossing the border ... from the U.S. side.
Indeed, for the first time since the Depression, there is an net outflow of Mexicans back to Mexico. While some might look at factors such as more aggressive deportation under Obama or lower Mexican birthrates — from an average of seven children down to two, they forget what motivated immigrants to come to the US in the first place: hopes of a better situation for them and their families.
It's what pushed the tidal waves of immigration in the 19th century, from Canada and China and so many European countries like Ireland. And many of these immigrants (or their children) have become very successful: Madonna (of Italian and French Canadian descent), Margaret Chow (of Korean descent), Kristi Yamaguchi (of Japanese descent), the Kennedy political clan (of Irish descent), Sergey Brin (the creator of Google, of Russian descent), and an uncountable number more.
But now, the tide is reversing. It shouldn't come as a surprise: Since the banking and housing sectors have crashed, the economy hasn't completely recovered, a first since 1945. And with the present (and disastrous) economic policies not helping the situation — such as quantitative easing, low interest rates, and bailouts handed to incompetent companies like GM — there is no end in sight, and whichever Republicrat is in D.C. won't make a difference. To add insult to injury, many people are renouncing their U.S. citizenship. With politicians wanting to tax even more out of people leaving the country or U.S. citizens living abroad, it might be a disincentive for rich and successful people to come to the U.S.
If politicians want the flow of immigration to stop or even to reverse, then they just need to keep their devastating economic policies that has put them 10th for economic freedom, with a noticeable decline since 2009 compared to Canada. But if they want the country to become the beacon of freedom and liberty it once was, then they need to radically change their ways.
First, they need to apply Reagan's motto: "Government is the problem, not the solution." It is not the government's job to decide what salary an employer must pay, nor how many vacation days it must give, nor is it to tell people to buy health insurance.
Second, they need to stop pretending that people "didn't build that." Yes, they did; and if government had any role in it, people had (usually) no other choice (roads, schools, bridges, etc.). Government and groups don't achieve anything; individual people do. Even the Pyramids weren't built by "the Egyptians"; they were built by individual Egyptian (and maybe people from elsewhere).
Finally, they need to stop (or at least severely curtail) this legalized theft named income tax. It is the most progressive one in the industrialized world which, in the long run, will either increase the black market, make people work less — which they already do, at rates not seen in 30 years — or make them move out of the country. Considering that "powers not granted to the federal government by the Constitution, nor prohibited to the States, are reserved to the States or the people," then there is no need for a federal income tax to fund a (defensive) militia and navy, Congress, tribunals, and regulation of commerce.
Until that happens, immigration to the U.S. will look uncertain and will have consequences, including notably decreased economic activity and loses for the agricultural sector. Mexicans aren't stealing any jobs; they are taking those nobody want.