1904 Presidential Election

[Deus Naturae]

Opposing a high tariff would, at the time, be a more populist position than favoring a high protective tariff.  It was a policy that benefited big corporations a ton, hence the GOP's loyal support for them.

Not necessarily. Lower tariffs were supported by Populists, but also (and more vigorously) by conservative Bourbon Democrats.

[Rockefeller GOP]

Opposing a high tariff would, at the time, be a more populist position than favoring a high protective tariff.  It was a policy that benefited big corporations a ton, hence the GOP's loyal support for them.

Not necessarily. Lower tariffs were supported by Populists, but also (and more vigorously) by conservative Bourbon Democrats.

The point is that the GOP (in my opinion, the more fiscally "conservative" party since its inception but at LEAST since 1896) supported a high tariff on pro-business principles.  It was certainly something populists attacked.  If I were to guess, Bourbon Democrats opposed it for partisan and electoral reasons.

[All Along The Watchtower]

Not all industries supported high tariffs, of course. Bourbon Democrats supported economic liberalism/trade liberalization for economic as well as ideological reasons.

Also keep in mind that the Bourbon Democrats were basically old-line Jacksonians who hadn't changed even as the country and political circumstances had changed.