Well first things first, food and energy. We need to be self reliant on food and energy the rest can wait. Oh and control of our borders is a must.
Not sure why this is relevant.
What we need to do is cut spending - reduce our indebtedness back to an acceptable level.
We are already self-reliant on food - while quite a bit of our produce is imported, our domestic grain, meat and dairy production provides probably 90% or more of the calories we consume.
We import some of our energy from abroad because it is cheaper that producing it here due to regulatory and labor costs. Cut government overhead and our domestic energy contribution grows automatically.
While government money is indeed spent on illegal immigration, that number pales in comparison to Medicare fraud, to cite one example.
Illegal immigration is, in terms of public finances, one of the least of our problems.
If we were to embark on a program of compulsory autarky in food and energy, our public indebtedness would go up, not down - and it would go up by much more than the savings realized on more aggressive border enforcement (which we do need).