China is actually our second largest foreign debt holder currently, behind Japan. I think both of them max out at about 7% of our total debt. The largest holder of American debt is America.
Most people speak with nothing more than emotion on immigration. For example I hear alot about how much immigrants cost us, with almost no mention of the things we take for granted that are cheaper because we are able to take advantage of immigrants.
The CBO found that "A bipartisan Senate bill that would create a path to legal status for many of the 11.5 million undocumented immigrants in the United States could reduce deficits by $175 billion over the first 10 years and by at least $700 billion in the second decade."
CBO: Immigration bill could cut deficits - Jun. 18, 2013
Many undocumented immigrants don't receive benefits of any kind. There is an issue to be seen in support for naturalized children of illegal immigrants, they end up costing taxpayers a significant amount. But our government views that as an investment - in that someday these hopefully educated children will become contributing tax payers.
If America and Mexico's situations were switched, and your option for your family was brave the cartel wars, people targeting your daughters for human trafficking and prostitution, and corruption all around you - and you were faced with the option of getting on a 4 million deep sometimes decade-long wait list for a visa you probably can't pay for...what would you do?