(CNN) When President Donald Trump talked to reporters Tuesday, he took questions on his travel ban, his promised wall and his tariffs -- all three of which are erecting barriers, physical or otherwise, between the US and other countries.

Given his unashamed "America First" nationalism, this was a very good day to look at all the barriers -- physical, personal and economic -- that Trump is starting to succeed in building.

His victory in the Supreme Court that upheld the latest version of the limited travel ban, which evolved from a campaign call to ban all Muslims from entering the US, keeps the US safer by shutting the country to groups of people from seven specific countries, according to Trump.

The ban ( and it is essential to read Saba Hamedy's piece on how it got from an official call for a total shutdown on Muslims entering the country to a semi-ban on people from seven countries ) is quite literally about keeping people out of the country because of where they come from.

At the southern border, meanwhile, Trump has been dealing with fallout from his decision to adopt a "zero-tolerance" policy toward undocumented immigrants. That the undocumented parents would be separated from their children during prosecution was seen as unfortunate collateral damage by the administration before widespread outcry made them reverse course.

The travel ban is meant to keep the country safe from terror attack, although there is scant evidence it alone will accomplish that. The zero-tolerance policy is supposed to keep the country safe from what Trump has referred to as an infestation of criminal immigrants . Both the travel ban and the zero-tolerance policy are meant to keep new people from coming into the country. Same with the administration's apparent decision to slow to a trickle US acceptance of refugees -- something related to but not entirely dependent on the travel ban.

The administration has also worked to kick refugees out of the country, including those from El Salvador and Haiti that have lived in the US for decades.

In Congress, Republicans are working on efforts to cut legal immigration by 40% in addition to cracking down on the illegal immigration that spends more time in the headlines.

That says nothing of the physical wall he has promised to build on the southern border and which is coming soon to news stories near you. It was at a meeting about trying to fund the wall that Trump first addressed the Supreme Court ruling on Tuesday.

The President has earlier made clear he could choose to shut down the government if Congress doesn't give him a big chunk of the $25 billion the government needs to get cracking on the wall he often said Mexico would pay for.

Asked today if the wall was worth a shutdown, he said, "No, no, we'll see. We'll see."

Which doesn't sound like a hard no.

On Tuesday, he distilled his campaign message into this bumper sticker: Strong borders, no crime.

That full quote is: "What we're looking for as Republicans, I can tell you, is strong borders, no crime. What the Democrats are looking at is open borders, which will bring tremendous crime. It will bring MS-13 and lots of others that we don't want to have in our country. ... So I will always be defending the sovereignty, the safety and the security of the American people."

The President has followed through in making Mexico (and Canada, for that matter) play hardball on the economy, thrusting new tariffs on those border countries and many others, including the EU.

While today he criticized Harley-Davidson for waving the "white flag" by moving some production to Europe to avoid retaliatory tariffs on US goods, he argued his tariffs are bringing countries begging to the US for new unilateral trade deals. Building up US trade barriers, he argued, will help tear down barriers other countries have built.

Clearly Harley-Davidson is no fan of Trump's tariffs, but he's as resolved on them (and his other barriers) as ever.