When someone harps on "securing the border", that's sometimes a clue that they're trying to fool people, as John McCain tried to do. After the border is "secure", some of them will push for an amnesty of some kind. We do need to secure the border, and not all those who harp on securing the border are being deceptive. Their other policies need to be taken into account.
For instance, if they say "secure the border first", you need to find out what's second and make sure it isn't some form of comprehensive immigration reform, aka amnesty.