At the time of Pulitzer Prize winning historian James McPherson's appointment in 1991, the US Senate was in Democrat control and the old confederate states were represented there by 14 Democrats.
Heflin, Shelby -AL, Bumpers, Pryor -AR, Graham -FL, Nunn -GA, Johnston, Breaux -LA, Ford -KY, Sasser, Mathews -TN Hollings -SC, Robb -VA, Byrd -WV
Does it seem unreasonable that one or more of these southern Democrats would have been able to block (within their own caucus) the appointment of a "marxist historian" to the Civil War Sites Advisory Comission?
Sure, but they didn't. Either they didn't look past his paper and didn't realize he was a Marxist, or they voted for him because they owed someone a favor. The people likely to have nominated a Marxist scholar like McPherson were not Southerners, was my point.