To determine the possible bias of each source when discussing the expansion of federal power in the 1930s and the reason for the bias, let’s consider the nature and typical stance of each source.
[tex]\[
\begin{array}{|c|c|c|c|}
\hline
\text{Source} & \text{A Heritage Foundation study} & \text{AFSCME's annual newsletter} & \text{An article in the Journal of American History} \\
\hline
\text{Possible Bias} & \text{against} & \text{for} & \text{none} \\
\hline
\text{Reason} & \begin{tabular}{l}
The Heritage Foundation is a \\
conservative think tank, likely to \\
oppose the expansion of federal power. \\
\end{tabular} & \begin{tabular}{l}
AFSCME is a public sector union, \\
likely to support expansion of \\
federal power which often benefits \\
public sector employees. \\
\end{tabular} & \begin{tabular}{l}
The Journal of American History is \\
a scholarly journal, expected to have \\
a neutral and academic perspective. \\
\end{tabular} \\
\hline
\end{array}
\][/tex]