The main supporters of Prohibition are as follows:
Women
Many women supported Prohibition because often times ther was lots of domestic abuse from drunk husbands/fathers.
A main group was the Women's Christian Temperance Union
Racists
Racists, like the KKK were big supporters of Prohibition. They believe that when African-Americans got their hands on alcohol, they would do horrible things. In fact, Frances Willard, a supporter of Prohibition once said, "the grogshop is the Negro's center of power. Better whiskey and more of it is the rallying cry of great dark-faced mobs"
Nationalists
Since most of the liquor was made by foreigners, many nationalists disliked it because they didn't like people from other countries. The Germans and Irish were the main brewers and distillers. Keep in mind that this is happening right after WW1, where Germany was our greatest enemy. Most people didn't like the German beer companies because they didn't like Germany. John Strange, a politician for Prohibition said "We have Germans enemies across the water. We have German enemies in this country too. And the worst of all the German enemies, the most treacherous, the most menacing, are Pabst, Schlitz, Blatz and Miller [beer companies]. In fact, there were lots of discriminatory acts against German-Americans. Governor William L. Harding of Iowa declared speaking German in public or on the telephone unlawful. German books were burned in Wisconsin, playing Beethoven in public was banned in Boston, and throughout the country foodstuffs and street names of German origin were denatured by benign Anglo-Saxonisms. Nearly ninety years before French fries became freedom fries during the Iraq War, sauerkraut became liberty cabbage in an odd homage to the president, Cincinnati's Berlin Street became Woodrow Street.
Religious People
Many very religious people were for Prohibition. One of the most famous was Billy Sunday, a Baseball player and then a preacher. To Sunday, liquor was 'God's worst enemy' and 'hell's best friend,' and he considered those who profited from the alcohol trade earthly Satans. "I will fight them till hell freezes over," he told a rally at the University of Michigan, where he persuaded 1,000 students to join the campaign for a statewide Prohibition law. "Then I'll buy a pair of skates and fight 'em on the ice."
Also, the main political group was the ASL, anti-saloon league. They started pressure politics, a form of campaigning for a cause that the NRA uses today.
For much mre information on Prohibition, I suggest that you read Last Call by Daniel Okrent
Yes
The violence of Al Capone and other organized crime leaders reduced support for Prohibition.
members of the public
President Roosevelt's platform included a plank calling for the repeal of Prohibition.
People didn't support it
National Prohibition in the US began in 1920 but support for it declined throughout the 1920s.
Many people around the world still support prohibition of alcohol,
They often joined the KKK because of its strong support of National Prohibition and its illegal enforcement of prohibition laws.
Prohibition can be seen as part of a cultural war against immigrants. That's one reason the KKK was such a strong supporter and (illegal) enforcer of prohibition laws.
The 1932 election.
Protestants, rural residents, members of the KKK, very religious people, and opponents of immigration tended to support prohibition.
Prohibition gained support before it was established but lost support throughout the 1920's and early 1930's. And opposition to it accelerated rapidly after the mid-1920's as the problems it created multiplied and became increasingly serious.