There's plenty of precedent for using the Insurrection Act.
Rutherford B. Hayes (R), October, 1878 -- to suppress the Lincoln County War
Grover Cleveland (D), July, 1894 -- the Pullman Strike (look into that one.)
Woodrow Wilson (D), April, 1914 -- the Colorado Coalfield War
Herbert Hoover (R), July 1932 -- the Bonus Marchers in D.C. (definitely look into that one)
Franklin D. Roosevelt (D), July, 1943 (while the military was already quite busy with other things) -- the Detroit race riot. Hmm, sound familiar?
Dwight D. Eisenhower (R), September, 1957 -- Protecting the Little Rock Nine
John F. Kennedy (D) - twice: September 1962, and September 1963 -- the first for The Battle of Oxford, the second to enforce desegregation of Alabama public schools.
Lyndon B. Johnson (D) - FOUR TIMES: July, 1967 -- '67 Detroit Riot, April, 1968 -- Washington DC riots, April 1968 -- Baltimore riots, April 1968 -- Chicago riots. 1968 was a year of widespread riots. Sound familiar?
George H.W. Bush (R) - twice: September 1989, Saint Croix, Virgin Islands in the aftermath of Hurricane Hugo, May, 1992 -- the Rodney King riots in LA.
Goodness. Do the Democrats REALLY want to double down?