How do I perform presidential proper noun declension?

Solution 1:

Coolidgean is in the Merriam-Webster dictionary, so even though it sounds really weird to me, I expect it's the most acceptable form.

Solution 2:

Washingtonian Adamsonian  Jeffersonian
Madisonian    Monrovian   Jacksonian
Burenian      Harrisonian Tylerian
Polkian       Taylorian   Filmorian
Pierceian     Buchananian Lincolnian
Johnsonian    Grantonian  Hayesian
Garfieldian   Arthurian   Clevelandian
Harrisonian   McKinleyan  Rooseveltian
Howardian     Wilsonian   Hardingian
Coolidgean    Hooverian   Trumanian
Eisenhoweran (can't find a cite for this, but maybe "Ikeian"?)
Kennedian     Nixonian    Fordian
Carterian     Reaganian   Bushonian
Clintonian    Obamaian

Of the above, some do not have common adjectival forms. The "Clintonian Doctrine" was standard, but then see the "Bush Doctrine." I would suggest the same for Eisenhower. Any of these that do not seem happy in the adjectival could probably be replaced with the name plainly.