Islamic governance

As-salamu `alaykum. Under Islamic law, can a woman be a nation's leader or be the head of any non-religious organization/body based on merit?

Respected scholars, as-salamu`alaykum. Are customs and taxes forms of injustice and thus, working as a tax collector would help to impose injustice? Is it allowable that a Muslim may evade paying them? Are they really important for the financial system of the state?Jazakum Allahu Khayran.