Well, Progressives and Democrats do not believe in boarders.  
In fact, they advocate for Open Boarders;

So, whats wrong with the ideal of the US Military going into Mexico to hunt down the Cartels who have been selling drugs in America, killing thousands of people annually and imprisoning the rest?  

You can’t have it both ways, you can’t have both secure borders and open borders and let the Cartels do whatever they want;  
Who else is tired of the border/wall debate, or the never ending Drug wars, if Mexico is a failed state and people are fleeing Mexico, Guatemala, Honduras, Nicaragua ext to America by the millions; 
Perhaps the US should Annex all of them starting with Mexico, thereby establishing one legal system all the way down to the Panama Cannel, where there is a water border between North and South America.