Aaron Rodgers' VP bid won't last long, but the Democratic party's still taking him plenty seriously ... at least, according to some high-ranking party members.

Top officials of the Democratic National Committee tell TMZ ... they're not taking any chances with Rodgers, even though they're expecting his VP candidacy to last as long as his first season with the New York Jets.

Basically, sources at the DNC tell us they're not writing off Rodgers or any other celebrity candidate no matter what they may think of them ... just look what happened with Trump.

DNC members acknowledge third-party candidates can easily play spoiler in a close election ... so all the more reason to face Robert F. Kennedy Jr. and possibly Rodgers head-on.