If There Were No Income Tax ...

If there were no Income Tax and no Estate Tax, then ...

A person's marital status would be irrelevant to the government.

And there would be no tax advantage or disadvantage to being married.

And then, people would be free to contractually make the living arrangements of their own choosing, regardless of the popularity or unpopularity of their choices.

And that way, the government and legal system would not be compelled to choose between equality and morality.

An oversimplification?  Perhaps.

But remember that it was a taxation issue that impelled Edith Windsor to pursue her case all the way up to the Supreme Court, and not the expressions of disapproval of her personal choices by moralistic prudes such as myself.