Currently, the Republicans claim to be the party of border security, while the Democrats claim to be the party of higher wages and better living standards for most. Until relatively recently, within my lifetime, wings of the Democratic Party actually championed all four ideals. While a liberal immigration policy, one that encourage people to come here for opportunity, has always been encouraged by many, illegal entrance into the country has not. Border security was seen by the most liberal Democrats as a way to lower crime in America's most at-risk neighborhoods torn apart by gang violence from illegally-smuggled weapons, as a way to ensure that employers paid decent wages to their workers, and as a means of fostering a civic virtue that could not be exploited by international corporations. Case and point: Cesar Chavez and Gene McCarthy
Throughout his life, Cesar Chavez crusaded for higher living standards for his fellow workers. He routinely organized the farm workers to strike for better wages, conditions, and treatment. A casual reader of US social history, one who has to rely on the media's tertiary sources because he's too busy working for a living to house himself and family, would be surprised to hear today that he staunchly opposed unenforced immigration laws until Reagan began encouraging illegal immigration as Governor of California. He would be even more surprised to hear that he was "persuaded" by Ronald Reagan and his supporters to change his tune, as Reagan would maintain close ties with United Fruit Company and its successors for his entire career, including his Presidency(this is another story.)
Gene McCarthy was the staunchest of liberals. If Barry Goldwater was Mr. Conservative, Gene McCarthy was certainly the closest thing to Mr. Liberal. He'd meet with Che Guevara to try to improve relations with hostile countries, and he'd co-sponsor the 1965 Immigration Act, which provided immigration opportunities to millions who'd previously been denied them. His philosophy was one of social welfare, diplomacy before war, higher taxes, and most significantly, opposition to illegal immigration. Horrified by the way corporations sneaked people, treated little better than peons, across our border to undercut workers, McCarthy advocated for border security throughout the rest of his political career.
By no means were these men perfect. Chavez would be persuaded by the Republicans to embrace illegal immigration and McCarthy would often let racist people infiltrate his organizations and derail his efforts, but its very important to point out that efforts to secure our borders fall thoroughly within America's liberal tradition of standing against corporate abuse and human trafficking. Furthermore, it is perfectly compatible with the desire to encourage immigration.
Since 1992, when Clinton(s) got McCarthy excluded from the debates to secure the nomination, border security has been shunned by most politicians of note. They somehow equate the desire for border security with bigotry and hostility to the world's struggling masses. The exact opposite is true: a secure American border provides more hope for Americans of all races and wealth inequality increases dramatically as companies use more and more illegal labor to pay substandard wages. Plus, a secure border in America helps Americans assist those struggling overseas and abroad.