Condition
Like other antiques and collectibles, the condition of political buttons greatly affects their value. Political buttons that still have the luster and eye appeal of a brand-new button have a much greater value than buttons with extensive wear and damage. Foxing, rust that creates dark spots on the button's image, and any defects that deface the political button reduce its value significantly. Unlike many other collectibles, damaged buttons can't be restored to their original condition.
Scarcity
The scarcity of a political button can affect its value, though the production quantity of a specific political button is virtually impossible to determine. Unlike comic books and stamps which have recorded production statistics, political buttons have historically been ordered from many different manufacturers during campaigns, and production statistics aren't usually collected. Still, items that rarely appear at auctions and trade shows will typically bring a premium from collectors.
Demand
Demand for political buttons fluctuates greatly from year to year, as the value collectors attach to political buttons featuring certain candidates or issues shifts. Demand for political buttons typically increases during election years, when new collectors enter the hobby. Momentous political events can affect the value of political buttons as well; when Barack Obama became the first presidential candidate to win his party's nomination, the value for Obama's senate and presidential campaign buttons rose dramatically.
Brummagem
Brummagem are counterfeit political buttons that have no value to collectors. The Federal Hobby Protection Act of 1973 prohibits brummagem from being sold as authentic vintage political buttons, but brummagem still frequently turns up at auctions, memorabilia shows and in private collections. It can be extremely difficult to determine if a political button is genuine; appraisal from experienced collectors or dealers is the best way to ascertain the authenticity and value of your political buttons.
Appraisal
While collectibles such as coins and comic books have annual price guides to provide the values of those items; there's no annual price guide for political button appraisal. Ted Hake's Encyclopedia of Political Buttons is the most commonly used reference by collectors, but it's not comprehensive and supplements are infrequently issued. Keeping track of what political buttons like yours are priced at in current auction catalogs and memorabilia conventions is the best way to determine what their approximate value is.