Thank you for this excellent question!
I think about this a lot. I believe it is absolutely appropriate for Christians to be involved in politics. William Wilberforce was a British parlimentarian in House of Commons from 1780-1825. When he became a Christian in 1785, he considered leaving politics, thinking it was in conflict with his new found faith. He consulted with John Newton and William Pitt and they encouraged him to remain in politics. He then found his political career could be informed by his faith.
He campaigned against slavery in the UK for twenty years until the passage of the Slave Trade Act of 1807. Not content with merely the cessation of the save trade, he continued to push for the freedom of the slaves which had already been traded! It wasn’t until 1833, just before he died that same year, that the Slavery Abolition Act was passed.
His belief that all men are created by God and, therefore, are made in His image and should be treated as such gave him the verve and resilience to fight so hard for so long. God used him in politics to do tremendous good for millions of people.
He also founded many societies in including the Royal Society for the Prevention of Cruelty to Animals (RSCPA) believing our responsibility as Christians extends to the animal world as well.
Joseph was used in a place of politics. Daniel was used in a place of politics. David and Solomon were both political figures. I believe that Christians are called to all spheres of influence, including politics.
We should stand firm, like Shadrach, Meshac, and Abednego, against corruption in politics. It is not the state or serving the state that is at issue. It is the deification of the state and serving it as one would an idol that is the issue. If you want to read more on that read “Being Truly Human” by David Gooding and John Lennox.
As a Christian in politics you can bring the light into a very dark situation. I understand that the stance on this is particularly controversial in South America with Liberation Theology. But, I believe there is a balanced position to be had on the matter.
I would love to hear your thoughts!