In a sense, however, those who acclaimed Jesus as king on that day so many years ago were not wrong to do so. In the 18th chapter of the Gospel of John, when questioned by the Roman governor Pilate, Jesus essentially acknowledges being a king. Moreover, His decision to enter Jerusalem on a donkey was not only (as is often emphasized) an expression of humility, but also an assertion of His kingship, for the donkey had been the royal mount of David and his successors. The problem was not that Jesus was not a king; the problem was that those in the crowd that day had a wrong idea of the nature of Jesus' kingship. Their concept of kingship was essentially political and human. However, as Jesus made clear to Pilate, His kingdom was spiritual in nature:
Jesus said, "My kingdom is not of this world. If it were, my servants would fight to prevent my arrest by the Jewish leaders. But now my kingdom is from another place." (John 18:36, NIV)
Moreover, the purpose of His kingship was "to testify to the truth" (John 18:37) and to accomplish the salvation of mankind and the vanquishing of death, not to carry out a particular political program.
Nevertheless, ever since that first Palm Sunday, the followers of Jesus (or at least, those who have professed to be His followers) have too often succumbed to that same political vision of the kingdom of God. This is evidenced by the entwining of church and state during the late Roman empire and the Middle Ages and even in later centuries (witness the establishment of state churches during the time of the Reformation). Unfortunately, even today Christians can fall prey to this temptation. In the United States, Christians inclined to one side or the other of the political spectrum have tended to be caught up in the idea that if certain laws were enacted and/or certain policies adopted by the government, the purposes of God's kingdom would be achieved. Those on the Left may speak of "social justice," while those on the Right may talk of "family values," but on a certain level they are really doing the same thing--confusing the kingdom of God with the kingdom of men.
By saying this, I am not suggesting that Christians should not care about politics. We were put into this world to be "salt and light," and that includes the political sphere. The Gospel certainly has implications for society, not just the individual. Moreover, I believe that those who by God's grace are living in countries where citizens have the privilege of participating in the political process should take advantage of that privilege, just as the Apostle Paul took advantage of his Roman citizenship. However, we should always be wary of the temptation of politics--to think that the purposes of God's kingdom can be primarily achieved through political means. In addition, I think we need to have a sense of humility, to avoid succumbing to the conceit that a certain set of political views represents the "politics of Jesus" (a la John Howard Yoder). Certain aspects of Jesus' teaching could be seen "liberal" or "progressive," while other aspects could be seen as "conservative." Yet what our Lord taught far transcends human political labels.
Moreover, by avoiding the temptation of expecting to bring about the divine purpose through human politics, we can also avoid the temptation of surrendering to despair when the laws or policies we favor are not adopted, or, perhaps even worse, when policies or laws are adopted that run counter to what we believe are the principles of God's kingdom. God shall accomplish His will ultimately by His own means and in His own time. In the end, "the kingdom of the world [will] become the kingdom of our Lord and of his Messiah, and he will reign for ever and ever" (Revelation 11:15, NIV). Then shall Jesus reign as king in every sense, including the political. May that day come soon!
Image of the Triumphal Entry from goodshepherdbh.org