JMHO, but I think all too often we think of the voting process as picking the candidate we most closely agree with and all too often we forget that the outcome of the process is the selection of the next president of the US. Since these are not necessarily the same thing, I cannot, in good conscience waste my vote on a third party.
With all due respect, that's a very myopic view. Voting for the lesser of two evils in the short term may nevertheless lead to more evil in the long term. If your conscience doesn't allow you to vote for the candidate on the ballot that you feel is best suited to be President, then the problem is that you have bought into the lie perpetuated by the two parties in power that wish to retain that power and keep it from outsiders.
I dare say the Founding Fathers would be absolutely disgusted at the notion of voting for the lesser of two enemies of freedom, to the detriment of a champion of freedom, because of the raw fear of governance at the hands of the greater enemy of freedom.
The lesser enemy of freedom is still an enemy.