How did we end up with millions of unregistered immigrants living in the U.S., some that have been here for 20 or 30 years? Why do we need immigrants, even legal? Immigration seems to be a hot button for most Republican candidates, even though illegal southern border crossings are at decades-lows. It is also a convenient enemy for President Donald Trump because they supposedly take all of the good jobs. Lets explore what caused our immigration situation and what the impacts are.

Who is to blame: I put most of the blame on the U.S. Congress who failed to enforce U.S. laws by neglecting to adequately fund border security and immigration courts for decades. They also failed to stop corrupt regimes and help failing economies in South American countries. The vast majority of Mexicans came to the U.S. to find work and live a decent life. It is our own fault that we have so many "Dreamers" in the U.S. now, so we need to find a way to accommodate them. Multiple administrations have failed to deal with this problem head-on in a thoughtful, compassionate way, including the Trump administration. Trump's zero-tolerance policy is neither thoughtful or compassionate, and separating children from their parents is cruel and un-American.

Secondly, I blame illegal drug use in the U.S., which created enormous demand, initially fueling cartels and gangs in Mexico and Colombia and more recently in Honduras, Guatemala and El Salvador. It is our fault that these drug cartels and gangs exist. It is our fault that gangs like MS13 make life unbearable for the residents of these countries. It is our fault that 30,000 Mexicans died in 2017 at the hands of cartels. None of this would have happened if not for the drug users in the U.S.

Are immigrants a security threat?

Gang members from MS13 should not be allowed into the U.S. The MS13 members already here are getting away with more crimes and getting stronger since Trump's deportation policies have made much of the Hispanic population afraid to call police.

Anyone who might commit a terrorist act should not be allowed into the US. The vast majority of terrorist acts are not committed by illegal immigrants, but instead by U.S. citizens influenced by foreign terrorist groups. We can start by banning guns from anyone on the "do not fly" list. Congress cannot even do that because the NRA lobbies against it.

Trump claims that 63,000 people were killed by illegal immigrants since 9/11. According to Snopes, the number of undocumented people arrested for murder during this period is more like 8,000. The statistics show that illegals have a murder rate almost half of the general population.

Are immigrants helpful and even desirable?

As the U.S. population ages and birth rates among whites decline, we need new immigrants to fill positions in our economy. As the demographic includes more and more retired people, the U.S. is facing serious deficits in the future that will reduce the funding for Social Security, Medicare and Medicaid. The only way we will meet the employment needs of our growing economy and provide benefits to our growing elderly population is to have significant immigration.

Contrary to what Trump claims, the majority of immigrants from South America do NOT take jobs away from citizens. They do the jobs that no one else wants to do, like picking crops, cleaning hotel rooms and other janitorial work. Without them, we would be hurting. The Trump administration's policies have already caused serious shortages of crop pickers and seasonal fishing workers.

We need to start valuing immigrants more; after all that's who built this country.