Fox News senior judicial analyst Judge Andrew Napolitano said Tuesday that as it stands, the only information that must be disclosed for the census is the total number of people who live in a residence.

Napolitano appeared on "Fox & Friends" on the same day the Supreme Court was to hear arguments over whether the 2020 census can include a question about citizenship, ensuring a quick review of a lower court ruling that blocked the Trump administration from doing that.

“The government is looking to acquire information about where people live and where people who are not authorized to be here live because that has a profound effect on federal aid to cities and has a profound effect on members of Congress,” said Napolitano.

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After hearing arguments, the high court is expected to announce a decision by late June.

Justices were slated to hear the case on Feb. 19, but in January, justices suspended oral arguments on the plan to add a citizenship question to the census next year. The justices put the matter on hold after a federal district court judge ruled the government could not proceed with its plans.

The Trump administration, though, then announced it would directly ask the Supreme Court to overrule the federal court judge, who said in a court opinion that such a question would dramatically reduce the response rate—and congressional representation—of non-citizens.

Napolitano said he doesn’t know which way the Supreme Court is going to go, but offered some insight as to what information must be provided as it currently stands.

“Now what a lot of people don't know is, the population consists of everybody who lives here, lawful or unlawful. And that number, that base number also affects the amount of money that the federal government gives to certain localities, depending upon a variety of formulas. So the argument in favor of this is, the more the government knows, the fairer it can be in the distribution of assets and the determination of how many members of Congress,” said Napolitano.

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“The other argument is, that people are afraid to answer truthfully because if they are here unlawfully, they think that’s it's going to result in their detention or deportation.”

He added, “If the census people come knocking at your door and say ‘What is your nationality?’ Do you have to answer? They’re not going to like what I'm about to tell you, the answer is no.”

He went on to explain the only question that must be answered, “How many people are living there? That, you have to answer.”

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Napolitano added, “You can ask any question you want and most people will think because the government is asking I must answer. But the only question you are obliged to answer is the total number of people who live there.”