Why did World War I veterans protest in Washington D. C. during the Great Depression

After World War I ended, many Army Veterans were given bonuses, in the form of certificates, which they could redeem in 1945 and get a compounded interest.

This was done under the 'World War Adjusted Compensation Act 1924'

However, the great depression had left many of these Veterans out of work and in miserable economic conditions.

In 1932, 17,000 veterans with supporters and affiliates marched on D. C. to ask the government to let them redeem these bonuses as soon as possible.