Writing at The Beacon Jonathan Bean nicely reminds us of Robert Whaples survey of economists and historians on questions in economic history. Among the questions that Whaples asked members of the Economic History Association to express agreement or disagreement on was the following:
Taken as a whole, government policies of the New Deal served to lengthen and deepen the Great Depression.
About half of the economists agreed (or agreed with some provisos) that the New Deal lengthened and deepened the Great Depression. Thus this point of view among economic historians is basically mainstream. Among historians there was much less agreement with the statement, although a significant minority, 27%, agreed, mostly with some provisos.