Is voting kufr? Some justify voting on the basis of Muslims paying tax to the government.

Answer

Voting is an un-Islamic system. This fact is sufficient to understand the impermissibility of participating in the system without valid need. Paying taxes is not a valid factor to justify indulgence in an un-Islamic system. Paying tax by itself is haraam. However, since tax is extracted by governmental coercive power, the people have no alternative but to pay.

Voting will be permissible only if a political party is a threat to the Muslim community or to Islam, and its policies are openly hostile to Islam and Muslims. In such a scenario it will be permissible to vote for the party which pledges to protect minority/religious groups and their rights. It is the need which dictates the ruling in cases of this nature. Nevertheless, despite voting being un-Islamic, it is not kufr.