There are facts and fugures on all sides of the argument as to whether or not these "illegal aliens" contribute or subtract from the tax base, from social service budgets and from the economy at large. Since I'm not qualified to say which side is right about all that (I'm not an economist or a statistician) I'm going to skip all that.
Just like money and goods and services cross the borders of the US, Canada and Mexico freely, people ought to be able to do the same. They do it in Europe and we should do it here. Every country that has free trade agreements with the US should also have free travel and work agreements similar to those within the European Union. Also there is a moral and ethical side to all this argument. One third of the Uninted States used to be one half of Mexico. On top of that the US has directly intervened and to a very great extent shaped the current ways of living in many countries of Latin America and the Philippines. Spanish is the defacto Second Language of the United States because the United States has been chin deep into the fabrics of Spanish speaking nations and peoples. It is not as if we have millions of newcomers, total strangers to our history, speaking Afrikaans or Yiddish and "not assimilating."
Here is a rundown of how the Europeans deal with the matters of internal labor market and rights of citizens of member nations within other member nations>
http://ec.europa.eu/justice_home/glossary/glossary_e_en.htm
elections
The process through which citizens elect representatives to democratic institutions. EU citizenship confers the right to participate and vote in elections for the European Parliament and local municipal elections, no matter which Member State the citizen resides in. (See EU citizenship: Political rights)
EU citizenship confers eligibility to stand and vote in elections for the European Parliament and local municipal elections, no matter in which Member State the citizens resides. . (See EU citizenship: Political rights)
employee
EU citizens are entitled to the same rights as an employee who is a national, no matter which Member State the citizen lives in. People from countries outside the EU are still subject to national immigration laws. (See EU citizenship, Immigration: Access to work)
employment
Under the Treaty of Amsterdam, employment is now enshrined as one of the European Communitys objectives. A new title on employment (Title VIII) in the EC Treaty states that employment is to be taken into consideration in other Community policies. (See Immigration: Access to work)
equality
EU citizenship confers the right to protection from discrimination on the grounds of, among other things, sex, race or ethnic origin, religion or belief, disability, age or sexual orientation. This is enshrined in the Charter of Fundamental Rights. (See Fundamental rights: EU Charter, Equality)
equal opportunities
Two key elements of the general principle of equal opportunities are the ban on discrimination on grounds of nationality (EC Treaty: Article 12) and equal pay for men and women (EC Treaty: Article 141). It is intended to apply to all fields, particularly economic, social, cultural and family life.
equal treatment
An important right conferred by EU citizenship. The Treaty of Amsterdam added a new Article 13 to the Treaty, reinforcing the principle of non-discrimination. Under this new article, the Council has the power to take appropriate action to combat discrimination based on sex, racial or ethnic origin, religion or belief, disability, age or sexual orientation. (See EU citizenship, Fundamental rights: Non-discrimination, Immigration: Integration of third-country nationals)
ethnic origin
EU citizenship confers the right to protection from discrimination on the grounds of, among other things, ethnic origin. This is enshrined in the Charter of Fundamental Rights. . (See EU citizenship, Fundamental rights: Non-discrimination)
EU citizenship
The 1991 Maastricht Treaty established the concept of European citizenship. EU citizenship confers a range of rights, including freedom of movement and the right to vote and stand in local and European elections in every Member State.