Constitution is foundation for the rule of law, while rule of law limits the government how it should be implementing different measures within the constitution to ensure rule of law prevails in the country.
Constitution separates powers, check and balance, justice system and other legal instruments, while rule of law can help just enforcement of these measures at all levels.
Constitutionalism as a system is designed to institutionally empower the governments and also limit their powers, while it lays foundation for the rule of law, explaining limits of the government.
Constitutionalism explains responsibilities of all state organs and agencies and rule of law acts and as a check and balance over these agencies to make sure they act about those responsibilities.
Constitutionalism is an institutional solution to different issues confronting state organs in determination of their responsibilities. It makes sure nobody interferes into powers and responsibilities of other agencies.
Constitutionalism ensures supremacy of constitution of the country, it makes all the government departments accept their responsibilities and practically take steps.
Constitutionalism is a system of the government that ensures protection of fundamental rights of all its people as human and citizen of the country. This protection is rights of all its citizens including minorities and different segments of the society.
The rule of law describes that all laws are democratically defined for all the citizens. It also ensures equality of before law and procedural justice.