Jeffy, I know reading is not fundamental to Trumpkins, lots of big words and such.  I please see below a link with graphics that show our current immigrant vetting process.  When you dream up or even if Trump dreams up a method of making this process more severe or costly, please post.  It's about a $4K process now, only really well funded Terrorist can afford it, ie. the Saudi Guys funded by bin Laden who actually did damage to us.  There has never been a terrorist attack on the US from any person from the 7 countries that Trump singled out.

https://obamawhitehouse.archives.gov/blog/2015/11/20/infographic-screening-process-refugee-entry-united-states