That simple question turns out to have a more than anticipated complex answer. The increased number of deportations is largely a result of a change in policy that began at the end of the Bush administration. Previously those caught within 100 miles of the border were simply rounded up, put on buses and let go at the border -- this policy was deemed "catch and release" and there was little documentation. Now the policy is those caught within 100 miles are documented (fingerprints, etc.) and then released. Some folks have been 'deported' many many times.
Conversely Obama determined that they would not pursue illegals outside of 100 miles. So if an illegal makes it to St. Louis the chance of him being deported is essentially zero -- unless he commits a felony. Sometimes not even then as they are in the judicial system and deportations from that part of the government is exceedingly rare.
As a result, human traffickers have developed a more complicated system that includes a 'trail' far beyond the border and into the heart of the country. From there local authorities have no ability to deport because the Obama policy turns a deaf ear to any local or state LE wanting to deport illegals. This change greatly increased the illegal 'migration' and it continues today.
Also, the human trafficking pipeline has proven particularly useful for also transporting drugs to places like Ottumwa, Iowa and Peoria, Illinois. Both of those towns are now essentially barrios and they're not the only ones. Illegals and drug-addled locals, that's small town America today.
Yeah, it's something of a shame, I suppose, but his administration's achievements and legacy can pretty much be summed up in three or four words: President-elect Donald Trump.
"Plenty of strikers can score goals," he said, gesturing to the famous old stands casting shadows around us.
"But a lot have found it difficult wearing the number 9 shirt for The Arsenal."