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Name just three.
Not quite sure whether you want me to recite conservative policy positions or riff about what I'd do if I were pope of this dump. The latter's more fun.
I guess I'd focus more on the demand side than the supply side. Building a physical wall, over some 1,200 miles, seems like overkill to me. After all, more Mexicans these days are going home than coming here.
I'd make it easier for employers to employ workers on the books. Reduce regulation, reduce benefit mandates, reduce the burden of tax compliance and reporting. If you can't politically cut the minimum wage, create a lower-tier wage for young Americans. Above all, promote economic growth so businesses and creative people have the means to employ those who want to work.
I liked the old Bracero program in some respects; workers needed to meet demand, often seasonal, could come here, work hard, and return home safe in the knowledge they'd be able to return the following season. Why is that important? Because most will choose to keep their families at home, where they won't be a burden on social services. That's a big unintended consequence of "walls". Make it hard to get in and folks will have a greater incentive to make sure their families follow.
Immigration policy should be focused on satisfying the needs of U.S. employers for the labor they need. It should be a dynamic policy, with the goal of increasing American competitiveness. Refugee policy is not the same as immigration policy. We let immigrants in to satisfy labor needs. When it comes to refugees, we should admit families, not unattached males.
I'm admittedly unconventional when it comes to tax policy. I'm one of those trogs who want to see a return of tariffs on imported goods, apolitical tariffs this time, that tax imported goods objectively on the basis of value added by foreign labor. Not a tariff set so high as to discourage competition, but that levels the playing field for American workers. Both parties are largely monolithic in that they favor cheap goods for consumers above all else.