I know that Islam looks at men and women in an equal light. However, I have heard that in Islam, it is not permissible for a woman to become the ruler of a nation? Is this the case, and if so, why?
This is not the case. In Islam, the election of the head of state is based on the vote of the majority. Whoever enjoys the confidence of the majority whether he is a man or a woman is legally eligible for this post.
However, the only debate which may remain is that whether women in general are suitable for this job regarding their temperament and nature. Nevertheless, if the majority does elect a woman for this post, no one has the authority to veto the opinion of the majority.
Here someone may present the following Hadīth to counter what has been said above:
عَنْ أَبِي بَكْرَةَ قَالَ لَقَدْ نَفَعَنِي اللَّهُ بِكَلِمَةٍ سَمِعْتُهَا مِنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَيَّامَ الْجَمَلِ بَعْدَ مَا كِدْتُ أَنْ أَلْحَقَ بِأَصْحَابِ الْجَمَلِ فَأُقَاتِلَ مَعَهُمْ قَالَ لَمَّا بَلَغَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّ أَهْلَ فَارِسَ قَدْ مَلَّكُوا عَلَيْهِمْ بِنْتَ كِسْرَى قَالَ لَنْ يُفْلِحَ قَوْمٌ وَلَّوْا أَمْرَهُمْ امْرَأَةً (بخاورى: رقم ٤٤٢٥)
Abū Bakrah says that he said: ‘Allah has given me the privilege of a word which I heard from the Messenger of Allah during the days of [the battle of] Al-Jamal, when I was about to join the people of Al-Jamal and fight with them’. When the Messenger of Allah heard that the people of Persia had appointed the daughter of Chosroes (Qisrā), he said: ‘People who appoint a woman as their leader will never succeed’. (Bukhārī, No: 4425)
However, in spite of being quoted in Bukhārī, it suffers from the following flaws:
1. It is a Gharīb Hadīth. In Hadīth parlance, a narrative which has just one narrator in any section of its chain is called Gharīb. It makes the narrative quite weak. It is only Abū Bakrah who is reporting this narrative at the top of this chain.
2. It is evident from the very text of the narrative that it was never known until the battle of Jamal took place. It was brought forward only after Ā’ishah (rta) faced ‘Alī (rta) in battle. Before that it was never heard of – which of course is quite strange.
3. Last but not least, if both the above two shortcomings are ignored and the Hadīth is interpreted to imply prohibition for a woman from being elected the head of state, then this Hadīth is against the Qur’ān. It is the purport of the Qur’ān (42:38) that anyone who enjoys the confidence of the majority is eligible to become the ruler of the Muslims. Nowhere does it exclude women from this general principle.