What word means to cancel or make ineffective?

I know that you might be able to use "eradicate".  It really depends on the context though.  If you're talking about canceling an order, eradicate would work.  If you're talking about and ineffective car itself, eradicate might not work.  :D

A. democrat, republican, whig, other.(the democratic and republican parties are the main 2 american political parties, the whig party was popular among the early presidents, and the “other” option allows for outliers)