I disagree... I think Reagan had a big heart and did the right thing with his amnesty act. They failed to secure the border following that act and that lead to a bigger problem. Obama was of the same mindset and I believe did the right thing with DACA. It was the humane thing to do. IMO it needs to go further... Secure the border, improve visa tracking, and provide a pathway to legal status for the undocumented people living in this country. I don't see why anybody would disagree with any of the 3 points I just made.
Reagan did have a big heart and it led to some bad policy decisions. At the same time, there was a demand for cheap labor at that time, especially from the southwest and within the Republican Party. It is always a mistake to choose not to enforce a law rather than to change it. Obama, imo, was just a politician who was interested in capturing the Hispanic vote.
President Trump is taking measures to enforce the law as it is written, while Reagan and Obama took measures to avoid enforcing the law as it is written. You can't effectively control the border if you send out the message, as Reagan did, that if you get here illegally, we will allow you to stay here on a year to year basis forever, or even worse, to send out the message, as Obama did, that if you get here illegally we will give you a path to citizenship. That's just bad policy and bad government.