A simple test of Faith in Jesus' power. Did Jesus in fact change the water into wine at the wedding of Canaan? Was it just a symbol? Was it only flavored water tasting like wine? Or, were the guests too drunk to know the difference?
Most conservative Protestants will understand the definition of "is" and find a former US President's perjury of his sexual relationship to be repugnant.
Thus, knowing full well the definition of "is", most Christians should recognize the Presence of Christ in the Holy Eucharist when he clearly states, "this is my body."
http://www.christiananswers.net/bible/luke22.html
When non-Apostalic Christian Faiths recognize the power of God's Word, when they must understand that His miracles were not mere symbolism. They'll be that much closer to being inside the Shepherd's fold then outside the gate.