It was President Hoover. Below is an excellent Historical summary of the bonus march. I don't believe that DC has a National Guard and as such is under the protection of the local police and our military.
http://www.thebonusarmy.com/smithsonian.php
MARCHING ON HISTORY
When a “Bonus Army” of World War I veterans converged on Washington in 1932 to demand a promised payment, MacArthur, Eisenhower and Patton were there to meet them
BY PAUL DICKSON AND THOMAS B. ALLEN
WASHINGTON, D.C., Chief of Police Pelham D. Glassford was driving south through New Jersey the night of May 21, 1932. Suddenly, a sight appeared in his headlights that he later described as “a bedraggled group of seventyfive or one hundred men and women marching cheerily along, singing and waving at the passing traffic.” One man carried an American flag and another a banner that read, “Bonus or a Job.” Glassford pulled over to have a word with the ragtag group. Atop one of the marchers’ pushcarts, he noted, an infant girl lay sleeping, nestled amid one family’s clothes, oblivious to the ruckus.
Glassford, who had been the youngest brigadier general in the Army in World War I, understood almost immediately who these wayfarers were. For two weeks or so, newspapers across the nation had begun carrying accounts of marchers bound for the nation’s capital. The demonstrators were part of a growing delegation of veterans and their families heading to Washington to collect payment of the “bonus,” promised eight years before, in 1924, to soldiers who had served in the Great War. (That year, wrangling over the federal budget had ordained that this compensation be deferred until 1945.) Now in 1932, the men, who called themselves the Bonus Army, were dubbing the deferred payment the “Tombstone Bonus,” because, they said, many of them would be dead by the time the government paid it. Glassford drove on to Washington.
By the time he got there, morning newspapers were carrying stories about the progress of the Bonus Army. The Washington Star reported that “One hundred unemployed World War veterans will leave Philadelphia tomorrow morning on freight trains for Washington” and that other vets were converging from as far away as “Portland, Oregon and the Middle West.” The chief was quick to grasp the logistical nightmare he faced. What he could not have seen was that the Bonus Army would help shape several figures who would soon assume larger roles on the world stage—including Douglas A. MacArthur, George S. Patton, Dwight D. Eisenhower and J. Edgar Hoover. The Bonus Army would also affect the presidential election of 1932, when the patrician governor of New York, Franklin Delano Roosevelt, squared off against incumbent President Herbert Hoover, widely blamed for the Great Depression then roiling the country.
In 1932, nearly 32,000 businesses failed. Unemployment had soared to almost 25 percent, leaving roughly one family out of every four without a breadwinner. Two million people wandered the country in a futile quest for work. Many of the homeless settled in communities of makeshift shacks called “Hoovervilles” after the president they blamed for their plight. Glassford knew he would have to create a sort of Hooverville of his own to house the Bonus Army. But where? In the end he chose a tract of land known as Anacostia Flats, at the outer reaches of the District of Columbia, which could be reached from Capitol Hill only by a wooden drawbridge spanning the Anacostia River.
Glassford oversaw the establishment of the camp as best he could, making sure that at least a certain amount of building materials—piles of lumber and boxes of nails—were supplied. The chief solicited food from local merchants and later added $773 out of his own pocket for provisions. The first contingent of Bonus Army marchers arrived May 23. Over the next two months, an estimated 25,000 more, many with wives and children, arrived to stake their claim to what they felt was their due.
Excerpted: The rest of this great write up can be read at the site/link:
http://www.thebonusarmy.com/smithsonian.php
Thanks Grampa, I bookmarked the site. That's an interesting and little known episode in our history.