Maybe we could find the answer from this article published by The Economist. Trump may be using the social unrest to canvass support from white voters.
From The Economist
"The violence in American cities reflects the fury of polarisation
America’s chronic anger could be its political undoing.
"THE SUMMER heat has its way of energising our political passions. The American and French revolutions both began in earnest with the sweltering June and July air stuck to each soldier’s skin. In 1967, a “long hot summer” of violence erupted throughout the United States as protesters against police brutality and racial injustice clashed with police and the national guard in most big cities. The following summer saw similar protests, and—like today—a hotly contested presidential election. The current unrest in America is similar in many ways to the riots of the 20th century, with young people and minorities expressing grievances over both racial inequality and the relationship with their government. But two recent developments serve both to worsen the tensions between protesters and their opponents and to decrease the chance that the government will find a solution: political polarisation and partisan rage.
The turmoil of 1968 is the most obvious parallel to today’s. Then, the Republican Party’s Richard Nixon and Spiro Agnew were the candidates of “law and order,” pledging to crack down on the violence and extend sentences for rioters. That year’s election was also a major catalyst for the marriage of race and political party in America. Nixon’s and Agnew’s electoral strategies probably helped them capitalise on the anger and anxiety of many white voters. In a new research article about the contest, Omar Wasow, a political scientist at Princeton University, finds that the year’s protests “likely caused a 1.5–7.9% shift among whites toward Republicans and tipped the election”. Since then, characterising protests as racial violence and promising to “crack down” on it has become a linchpin of the Republican Party’s electoral playbook.
The Republican politicisation of protests has continued to the present. Donald Trump’s rise in 2016 has been linked to his continuing campaign against immigration across the southern border, but many of his supporters may have had the Ferguson and Baltimore riots of the mid-2010s in the back of their mind. It is no empty generalisation to say that Republicans rely on whites—and Democrats, non-whites—for their electoral successes; according to a study published by the Pew Research Centre on June 2nd, 81% of Republican voters are white, whereas only 59% of Democrats are. Offered a choice between Joe Biden and Mr Trump, African-Americans pick the Democrats’ presidential candidate nearly 90% of the time, according to The Economist’s latest polling data from YouGov.
The Republican Party’s increasing whiteness over the years has made it less amenable to making progress on racial justice. Although white voters generally agree with African-Americans’ grievances on police brutality, they focus on the violence and looting in the ensuing protests rather than on the broader social context. A majority of both whites and Republicans told YouGov that they thought race was a major or minor cause of George Floyd’s death, for example. But most also said that the protests were the result of black Americans’ “long-standing bias against the police” rather than “a genuine desire to hold police officers accountable”.
White Democrats, on the other hand, have moved to the left on racial issues, a product of political polarisation and “partisan sorting”. As Democratic elites adopted the ideas of African-American activists, so did the liberal whites who remained in the party. This has also changed the portrait of the average protester. Black Americans protesting against police violence are now joined by whites and Hispanics, the young and the old. Demonstrating against police brutality has become political and ideological, not just racial.
The big, angry sort
Over the past 60 years America’s political parties have not only grown further apart racially; they have also become angrier at each other. In “American Rage”, a forthcoming book on the subject, Steven Webster, a political scientist at Indiana University, finds that Americans’ ratings of the opposing party have dropped by roughly 40% since 1960, from an average of 50 to 30 out of 100. Party identification is not only a product of positive association with one side of the aisle, Mr Webster argues, but also a statement of negativity toward the other. He theorises that voters have been baited by the media and political leaders to view the other side as fundamental threats to their livelihood; as a group to be detested, not to work with.
Crucially, Mr Webster finds that both parties have their fair share of angry voters. Some in unsavoury corners of the right shout for “law and order”; anger on the left spills into rioting and looting. And he argues that this anger is a fundamental threat to the American government. Mr Webster says that when people shift from being emotionally angry (eg, in response to a police shooting) to being habitually so (eg, routinely demonstrating violently against the state) they “lose trust in the national government, lose their commitment to democratic norms and values and weaken in their commitment to minority rights. They think people who disagree with them politically are a threat to the country’s well being.”
In short, the racial anger manipulated by Nixon and Mr Trump is not just a political tool, but also damaging to the country. So too is the anger among some Democrats toward the police. Mr Webster says that the short-term capitalisation of Republicans on the fury of angry whites is a long-standing political strategy, “but this time we might also find a manipulation of the protesters by the left.” Elite Democrats are likely to tell supporters they ought to be angry at police brutality, they ought to be angry at systemic racism and that they ought to be angry at the president. Why? “Because an angry voter is a loyal voter,” says Mr Webster. He finds that 30-40% of voters who feel angry some or all of the time are so-called “negative partisans”—the ones who view the other party as threats to the country and unworthy of their votes. In contrast, the majority of voters who rarely or never feel angry are much more co-operative.
This year’s presidential election has mostly been void of the angry politics of race. The president has campaigned (and tweeted) much more about socialism and restrictions on movement stemming from the coronavirus. Now Mr Trump may return to the same politics of racial division that served him last time. Speaking in the White House rose garden on June 1st, he called protesters “thugs”, “criminals” and “looters”, and pledged “severe criminal penalties and lengthy sentences in jail”. Such language has historically served as code to some white voters that Republicans stand with them against the “violent mobs” (Mr Trump again) of African-Americans threatening their peace. There is little doubt the campaign will become racialised.
If Democrats fall prey to this familiar trap, defending the riots in the name of racial justice, the mobilisation of anger around George Floyd’s murder could meet an ill-fated, politicised end. But if activists remain non-violent and reserved in their protests against brutality and racial injustice, America may be able to make some sorely needed progress on police reform and racial inequality."