From the New York Times article on the plan:
"Like other Democratic presidential hopefuls, Mr. Biden would roll back Trump administration immigration policies, including its practice of forcing migrant families to wait in dangerous areas of Mexico for the duration of their immigration cases and limiting the number of asylum seekers who can apply for protection at entry points along the border. Mr. Biden would also reinstate Deferred Action for Childhood Arrivals, or DACA, which Mr. Trump has moved to end. The program, created during the Obama administration, shields young immigrants known as Dreamers from deportation....
As a longer-term goal, Mr. Biden’s plan calls for an overhaul of the country’s immigration system, including providing a path to citizenship for people who are in the country illegally. He also wants to allow cities and counties to petition for more visas for immigrants to support economic growth....
Despite a push on the left to abolish Immigration and Customs Enforcement, or ICE, Mr. Biden’s plan stops short of seeking that or even outlining any major restructuring of the agency. His plan says his administration would ensure that personnel at ICE, as well as at Customs and Border Protection, “abide by professional standards and are held accountable for inhumane treatment.”
Mr. Biden’s plan does not call for decriminalizing unauthorized border crossings, a move supported by some other Democratic presidential candidates. Asked at a debate in June whether they believed that crossing the border without documentation should be a civil offense instead of a crime, most of the candidates onstage raised their hands. Mr. Biden raised a finger.
The next week, in an interview on CNN, he said he did not support the decriminalization of such crossings. “I think people should have to get in line, but if people are coming because they’re actually seeking asylum, they should have a chance to make their case,” he said."
So far, so good. As political scientist Marc Hetherington has said (quoted by Tom Edsall):
"Liberal Democrats don’t seem to realize they are out of step with the rest of the American public when it comes to immigration and racial attitudes...,Most consequentially, liberals seem to think that surely most Americans are fine with more porous borders. It would be cold and heartless for people to believe otherwise, not to mention economically shortsighted....[liberal faith in widespread support for immigration] is not even remotely true.”
And that gets to the heart of some Democrats' cultural (not economic) vulnerabilities as potential general election candidates. As Ed Luce noted in a Financial Times column:
"People in the middle, who may quietly support gay marriage but attend churches that do not, or who sympathise with illegal immigrants but want a secure US-Mexico border, feel looked down upon. Implying that those who disagree with you are backward is a poor way of winning their vote."
After the UK election results, perhaps we should take this problem more seriously and not assume a robustly progressive economic program (as popular as that may be) will cure all electoral ills.