But it turns out that fixing the marriage penalty is much harder than making a speech. The problems are both fiscal and philosophical. The philosophical debate may be even more divisive, and it illustrates perfectly the problem of using the tax code to promote the goals of social engineering. The government has long understood that it can manipulate public actions by levying higher taxes on undesirable behaviors while encouraging other behaviors through tax breaks. Looked at in this way, the marriage penalty is particularly objectionable.
Conservatives argue, rightly, that it is in effect a sin tax on the institution of marriage.
Regardless of the cost to the Treasury, they insist it must go because of the message that it sends about the desirability of marriage. Married couples would then be treated exactly the same as unmarried couples, and the incentive for living together outside of wedlock would be erased. Surprisingly enough, the loudest objections have come from the pro-family lobby. He actually paid less tax as a married man than he did as a single because Querube didn't work outside the home. It's only when she goes to work that the marriage penalty kicks in.