Yes, they can.
There is no law against 2nd cousins getting married.
Yes, second cousins can legally get married.
That's just nasty.
Third cousins can marry in all states of the United States. Abut half the states forbid marriages of first cousins; none forbid marriages of second cousins.
The children of your first cousins are your children's second cousins.The children of your second cousins are your children's third cousins,And so forth.
The children of your parent's first cousins are your second cousins. The children of your parent's second cousins are your third cousins.
Your second cousin's siblings are also your second cousins. The children of your second cousins are your second cousins, once removed.
The children of your mother's first cousins are your second cousins. The children of your mother's second cousins are your third cousins. And so forth.
The children of your mother's first cousins are your second cousins. The children of your mother's second cousins are your third cousins.
The children of your mother's first cousins are your second cousins. The children of your mother's second cousins are your third cousins. The children of your mother's third cousins are your fourth cousins. And so forth.
The children of your mother's first cousins are your second cousins. The children of your mother's second cousins are your third cousins. And so forth.
Whether or not Robin Cousins has been or is married is open to speculation because Cousins is exceedingly private about his personal life.