A Christian's journey towards heaven is infinitely more important than politics. However, I saw a slight parallel between the unseen benefits of both Christian living and third party voting, and I wanted to share it with you.

A Christian, ideally, is very much in tune with the idea of unseen benefits. After all, God our Father is unseen. So is faith. So is heaven. Christianity is dead without the physically imperceivable. Indeed, 2 Corinthians 4 illustrates Paul's hope in the unseen:

16Therefore we do not lose heart. Though outwardly we are wasting away, yet inwardly we are being renewed day by day. 17For our light and momentary troubles are achieving for us an eternal glory that far outweighs them all. 18So we fix our eyes not on what is seen, but on what is unseen. For what is seen is temporary, but what is unseen is eternal.

As it relates to suffrage...

I'm sure you've heard someone say that voting for a third party candidate is a wasted vote. Supposedly, your vote is "wasted" because the candidate never had a chance of winning. This is possibly a true statement, but let's consider the unseen benefits of "wasting" your vote. For the remainder of this post, "wasting your vote" will (slightly-less-verbosely) refer to voting for a third party candidate.
Ralph Nader, Ron Paul

Perhaps you hold Libertarian views but always vote Republican. Or perhaps you're attracted to the Green party, but when elections roll around, the Democrats have your vote firmly in their pocket. If you decided to start wasting your vote on an alternative candidate, you would probably not see an immediate benefit. Even after wasting your vote for serveral election cycles, you might not see one bit of progress. Your benefits are unseen though, and moreso if you attract more people to waste votes with you.

As politicians see that portions of their traditional voter base

“Perhaps voting Christians should not think of "wasted votes" as such, but as investing in unseen positive change.”

(i.e. gun owners or church go-ers for the Republican party) are increasingly voting Libertarian (for example), perhaps candidates will wake up and try to win them back. On the other hand, if Republican politicians see that their traditional demographics are blindly supporting them regardless of policy, will they not commence wooing the center-left leaning voters? A vote is a vote; you cannot physically fasten a statement to your ballot, but you can make a statement. After a while, if enough people stick with wasting their votes, one might very well observe positive changes in the mainstream political parties.

The Christian Parallel of "Wasting Votes"

To an unbeliever, a Christian's adherence to Christian principles might seem like he is wasting his life. Why spend time in prayer? Does it ever work? Why deprive yourself of material extravagance or promiscuity? Why spend time reading the Bible? Does it ever help? Does it ever benefit you? Yes. It does. The benefits are not guaranteed immediately though. In fact, they're not even guaranteed in this lifetime! The following verses from Hebrews 11 tell us so:

1Now faith is being sure of what we hope for and certain of what we do not see. 2This is what the ancients were commended for.
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13All these people were still living by faith when they died. They did not receive the things promised; they only saw them and welcomed them from a distance. And they admitted that they were aliens and strangers on earth.
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16Instead, they were longing for a better country—a heavenly one. Therefore God is not ashamed to be called their God, for he has prepared a city for them.
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39These were all commended for their faith, yet none of them received what had been promised. 40God had planned something better for us so that only together with us would they be made perfect.

Although Christians can see earthly benefits from their self-imposed "life-wasting" actions, the ultimate benefit is unseen: a home in Heaven, with perfect communion with God. No one alive has ever seen that before. Perhaps voting Christians should not think of "wasted votes" as such, but as investing in unseen positive change.