The illegal aliens are a bipartisan scandal. DemocRATS want the votes and dependency, while many establishment Republicans want cheap labor for their campaign contributors.
You might be surprised at how many 'Rat campaign contributors like cheap labor for their businesses as well.
Despite 'Rat efforts to demonize the GOP as the "party of Big Business and Wall Street," the reality is that corporations of all sizes and types of employees contribute to either or both parties.