The US Supreme Court has ruled that same-sex marriage is a legal right for all Americans in a historic 5-4 decision.

Writing the majority opinion, Justice Anthony Kennedy argued that marriage was a constitutional right for all under the 14th Amendment, saying “no union is more profound than marriage”.

Before the decision, gay marriage had already been found to be legal in 37 states across the US, but all states will now be legally obligated to allow gay and lesbian couples to marry. However, it is unclear how long the states that did not previously allow gay marriage will take before they begin to issue marriage licenses.

Loud cheers erupted from the crowds gathered outside the Supreme Court as the ruling was announced.

US President Barack Obama welcomed the decision, describing it on Twitter as a ‘win for love’. He said:

“Today is a big step in our march toward equality. Gay and lesbian couples now have the right to marry, just like anyone else.”

Gay marriage is a major step for gay rights in the US with same sex couples treated equally before the law. However, marriage equality means divorce equality and in future years this will mean gay couples also treated equally by divorce lawyers, but for now it is a time for celebration.