Paraphrase:
Land Party's one political victory took place in 1935.
Most of its support that year was from rural and rural-ish areas. Economic problems had hit that agricultural sector of the pop. hardest and Land Party targeted those groups. Conclusion: Land Party's success was due to combination of specifically addressing the concerns of those groups, and because of the economic problems.
Stem: Each of the following, if true, strengthens the historian's argument EXCEPT: