The focus of the outstanding new movie, The Green Book, is on a concert tour that included the Deep South made by Dr. Don Shirley, a brilliant African-American classical pianist. He is accompanied by Tony Vallelonga, a white man from the Bronx as his driver and bodyguard. Their experiences, portrayed as happening over an eight-week tour in late 1962, actually occurred over the course of multiple tours extending over 18 months.

The Negro Motorist Green Book was a guide for African Americans first published in 1936 advising them where they could find food, lodging, and gas stations that would serve them as they traveled in the South. The year 1962 is well within the lifetimes of many of us and right before the passage of the radically transformative Civil Rights Act of 1964 that opened up public accommodations without regard to race.

The film’s protagonists contend with Jim Crow laws, a form of racial discrimination enforced by law that encompassed all aspects of life, even including curfews that prohibited African Americans from entering city limits after dark in multiple Southern municipalities.

In many ways we’ve come very far; yet in other ways, we’re still trying to find our way as a society to full racial equality. The movement toward that goal has had many twists along the way with lots of backward as well as forward steps in the time since the end of slavery. Some of those twists are truly ironical. One is news that President Trump has recently been looking into the possibility of amending the Posse Comitatus Act.

That act was passed in 1878 as one of the final steps to assure the complete removal from the South of federal troops as policers of safety for African Americans and enforcers of local laws for the protection of citizens. Those troops were in place in the South from the close of the Civil War through the end of President Ulysses S. Grant’s second term in office. Grant had been determined to protect the new rights of former slaves. His use of federal troops in the South was intended, and did, hold in check to a considerable degree the depredations of the Ku Klux Klan (that was suppressed around 1871 by these federal troops in its first manifestation but, of course, reappeared in force later) and other vigilante groups, and even local-government-sponsored forces, intent on terrorizing African Americans.

As Grant’s presidency ended and “Reconstructed” formerly Confederate states returned to full statehood, Southern representatives in Congress were able to secure the passage of measures like the Posse Comitatus Act. The act prohibited the use of federal troops to enforce laws within the states and permitted the resurrection of the KKK and similar terrorist groups. Revising this law — designed to thwart the use of federal power to protect minority group members — in order to serve Trump’s border purposes is certainly ironical.

With the end of Grant’s terms in office, the mood of the country was once again to ignore what the South was doing to oppress its African-American citizens, and the era of Jim Crow enforced a new form of slavery on Southern African-Americans the effects of which extended in their most virulent form for almost a century, as The Green Book film illustrates so well.

Northern whites were no saints in this process as they turned a blind eye to what was happening in the South and de facto segregation continued in the North. In fact, our nation as a whole, at the federal as well as individual state level, enforced segregation in federal housing projects nationwide from the New Deal forward. That government-sponsored segregation ramped up even more as part of the massive post-World War II federal programs designed to provide new housing especially for returning veterans. The VA and FHA, both federal government agencies, used red-lining in the North as well as in the South to restrict housing purchases on racial lines. Their rules were vigorously enforced, and they operated in parallel with restrictive local zoning laws established across the country (even here in Connecticut) to assure housing segregation to the maximum extent possible. With this racially restrictive housing came neighborhood schools that reflected the same segregated composition.

We’re still working our way as a nation through the consequences of these government policies. The Green Book is a stark and stirring reminder of how far we’ve come but also a cautionary tale about how far we still need to go to full racial equality. It’s a film we all need to see.