The Chasidic commentator Rabbi Simcha Bunin of P'shischa claimed that the repetition meant that not only did one have to administer justice fairly, but you had to appear to do so; there could be no question of your probity. Abraham ibn Ezra, the great rationalist of medieval commentators, actually did suggest that the doubling may just have been added for emphasis. But Ibn Ezra was not only a great contrarian; he was also a great grammarian, and he knew that Hebrew often repeats a work as a way of marking continuity. Thus, sof is the Hebrew word for "end." When it is repeated –sof, sof–it means "finally." So, ibn Ezra conjectures, perhaps tzedek tzedek tirdof means that you are to pursue justice finally, that is, "as long as you exist."

[Tzedek Tzedek Tirdof] fits within the general topic of the beginning of this parashah: a set of commandments to appoint judges, shoftim. In the very next verse, however, the Torah appears to introduce an unrelated subject: "You shall not set up a sacred post [asheirah] any kind of pole beside the altar of the Eternal your God that you may make- . . . for such the Eternal your God detests" (Deuteronomy 16:21-22). According to the best modern scholarship, an asheirah was a cultic object, made of wood, for the worship of a Canaanite god-or more likely goddess, such as the goddess Asheirah. Traditional Rabbinic commentary, while agreeing that an asheirah was an object for idolatrous worship, preferred to think of it as not a carving but an actual tree. The juxtaposition of these verses–those about justice and those about the idolatrous tree– led the Talmud to suggest that the appointment of an unworthy judge was akin to planting an idolatrous tree. That is to say, a miscarriage of justice is like the planting of a tree that encourages evil and idolatrous practices.
-Rabbi Thomas Alpert

Between the end of Reconstruction in 1877 and 1950, a total of 4,084 terror lynchings took place in twelve Southern states, and 800 more occurred in other states of the Union. Especially in the South, where the vast majority of these actions occurred, whites lynched Blacks to ensure continued racial control after the end of slavery. They were able to do so because the remainder of the country chose to let them.

It is not that the larger population did not know what was going on. In 1882, the pioneering Black journalist Ida B. Wells detailed the situation in her pamphlet Southern Horrors. In 1909, she helped found the National Association for the Advancement of Colored People (NAACP), which carried on the work of fighting to end lynching. Starting in 1920, it displayed a banner outside its national headquarters on Fifth Avenue in New York City. In large white letters on a black background, it read, "A MAN WAS LYNCHED YESTERDAY." The banner went up whenever the NAACP leadership heard of a reason to fly it. Someone passing by on one of the great thoroughfares of the largest city in the United States would have been hard put not to see it. The NAACP stopped flying it in 1938. Lynchings hadn't ended; rather, the landlord threatened the organization with legal action if it didn't desist. The NAACP and its allies sought to outlaw lynching at the federal level, but Senate filibusters doomed them. To this day, lynching is not a federal crime.
-Rabbi Thomas M. Alpert

Tzedek, tzedek tirdof. "Justice, justice you shall pursue." The midrash was right: going in search of a court that will do your bidding degrades a society. That is one thing that lynching did: it set up its own vision of justice, a white people's court, where there was no place for an alternative point of view. And Simcha Bunim was right: the appearance of justice is as vital as the fact of justice. We can't take a noose thrown over a tree lightly, even if someone claims it to be a joke. An idolatrous tree is always calling. But perhaps most of all, Ibn Ezra had it right: we have to pursue justice again and again, for as long as we exist.

The miscarriage of justice is a tree that will bear strange fruit. We must uproot it if we are to endure long in a good and precious land.
-Rabbi Thomas M. Alpert