It does make a difference. Regardless of your party affiliation, speaking from the point of view which party favors MJ, Democrats are much more pro MJ than republicans.
The last poll I saw showed Dems were pro MJ legalization in high 70% where as Repubs were only about little over 50%. Last poll that I saw earlier this year had 64% in favor of legalizing MJ. That number is likely higher now.