Many Christians wouldn’t call it necessary but would see it as compromising the faith.
Shortly after Mitt Romney met with Billy and Franklin Graham earlier this month, the Billy Graham Evangelistic Association quietly removed Mormonism from the list of religious cults on the organization’s website and then ran an ad in newspapers around the country urging Christians to “vote biblical values” in November.
Today, Franklin Graham explained that it was necessary for them to take this stand on behalf of Romney because
“we believe this is one of the most important elections in our lifetime” and “this could be America’s last call to repentance and faith in Jesus Christ.” As such, it is vital that Christians vote properly, because failure to do so will leave America “ripe for God’s judgment” Link
The Word says it is the little foxes that spoil the vine. Compromising on issues of the faith, even for what you perceive as a ‘good cause’ is giving heed to the little foxes;
Catch us the foxes, the little foxes, that spoil the vines: for our vines have tender grapes. (Song of Solomon 2:15)
By foxes may be meant false teachers, to whom the false prophets of old were compared, Ezekiel 13:3; foxes are crafty and subtle creatures, malignant and mischievous, hungry and voracious, full of deceit and dissimulation, are of an ill smell, and abominably filthy; so false teachers walk in craftiness, use good words and fair speeches, and thereby deceive the hearts of the simple; their doctrines are pernicious, their heresies damnable, and they bring destruction on themselves and others….they put on sheep’s clothing, transform themselves into angels of light, mimic the voice of Gospel ministers, use their phrases and expressions, that they may not be easily discovered; and are abominable in their principles and practices, and to be shunned by all good men. Now ministers of the Gospel are ordered to take these, to detect them, and refute their errors, and reprove them sharply for them: (From Gill’s Exposition of the Bible: Song of Solomon 2:15 )