The recent desecration of Jewish cemeteries in Philadelphia and St. Louis, nearly 100 bomb threats made against Jewish day schools and community centers across the nation in just two months this year, and last week's possibly racially motivated killing of a Kansas man of Indian descent provide more evidence that America is witnessing a surge of hate crimes.

Many people are asking why President Donald Trump is not doing more to address these violent acts. Although he should be showing leadership and making every effort to quell this tide, he is not. Trump's first speech to Congress would provide a perfect opportunity to make a forceful statement against hate, should he choose to take advantage of it.

No one is accusing Trump and his advisers of vandalizing Jewish gravestones or gunning down immigrants. But that does not mean Trump bears no responsibility for the ever-increasing toxic environment in America. The man who inhabits the Oval Office is part of the problem -- by helping to create an environment of hate, intolerance and scapegoating, where people live in fear because of their race, ethnicity, religion, immigrant status or sexual orientation.

Throughout the election season, the Trump campaign fueled the fires of nativism, xenophobia and bigotry with promises to build a wall on the US-Mexico border. Donald Trump the candidate stereotyped Latino immigrants as rapists and murderers, and vowed to round up undocumented immigrants and create a Muslim registry reminiscent of Nazi Germany.

In his rallies, he whipped the crowds into a frenzy and openly encouraged acts of violence against protesters. And although he claimed he had never heard of David Duke -- the former KKK grand wizard who endorsed him -- candidate Trump enjoyed the support of white nationalists and hate groups who made robocalls on his behalf.

Now, under the new President, white nationalists and their enablers such as ex-Breitbart chief Stephen Bannon and Stephen Miller are crafting policies out of the West Wing and writing speeches laced with Islamophobia and evoking the "America First" theme that was freighted with anti-Semitism when it surfaced among isolationists in 1940. While Trump said he is "the least anti-Semitic person that you've ever seen in your entire life" and "the least racist person," the refusal of this White House to mention the Jewish genocide on International Holocaust Remembrance Day because others died, too -- as if to say "all lives matter" -- speaks volumes.

In many ways, Trump is reminiscent of the segregationist Southern politicians of the 1950s and 1960s who kept their hands "clean" on the surface while they enacted humiliating, unjust and oppressive policies against African-Americans. They vilified and criminalized black people, railed against civil rights and so-called race mixing, and stood in front of the schoolhouse door with dramatic effect to preserve Jim Crow. With a wink and a nod, they tacitly sanctioned the acts of Klan violence that resulted.

The world's greatest bully pulpit can be used to bring people together or exacerbate tensions and sow the seeds of division. At this moment, it accomplishes the latter.

If the Trump administration wanted to demonstrate a true commitment to reducing hate crimes, there are concrete steps it could take. First, Trump should speak out more forcefully and decisively against hate crimes and insist that this is unacceptable and will not be tolerated. As the Anne Frank Center asked in a tweet, "(I)f you can respond to SNL immediately, why can't you respond to #antisemitism immediately?"

He can take a lesson from Philadelphia Mayor Jim Kenney, who issued a statement immediately after the cemetery vandalism: "My heart breaks for the families who found their loved ones' headstones toppled this morning. We are doing all we can to find the perpetrators who desecrated this final resting place, and they will be prosecuted to the fullest extent of the law," Kenney said. "Hate is not permissible in Philadelphia. I encourage Philadelphians to stand with our Jewish brothers and sisters and to show them that we are the City of Brotherly Love and Sisterly Affection."

This is the type of leadership that quashes such expressions of hate and sends a clear message that these acts are unacceptable. The White House must take seriously the threat of white supremacist hate groups and homegrown domestic terrorism.

In one government program that counters violent extremism, Trump wants to focus solely on radical Islamic extremism and ignore violent white supremacist groups altogether. Instead he should promise that the Justice Department will investigate and prosecute all hate crimes. This would require an attorney general other than Jeff Sessions, someone who is not hostile toward civil rights and hate crimes protections for LGBT people, and is not affiliated with anti-immigrant and Islamophobic extremists.

Finally, Trump cannot make this about himself, but rather about a nation that is in a bad way. It is insufficient to say he has a Jewish daughter and grandchildren. After all, Thomas Jefferson had black children, and he enslaved them. Trump must take hate crimes seriously, condemn them and walk the talk with just and righteous policies that affirm human dignity. That is impossible when the alt-right movement and Bannon, the former leader of Breitbart, appear to be running the White House.

This commentary originally appeared on CNN.com