Chief Justice John Roberts was planning to vote in favor of President Trump's citizenship question on the 2020 census before reversing course and striking it down.

Sources familiar with Supreme Court deliberations told CNN on Thursday that Roberts, 64, had initially planned on supporting the census question after hearing oral arguments in April. Roberts changed his mind after believing the reason for the question was invented rather than necessary.

Roberts' decision is similar to his one to uphold The Affordable Care Act in 2012 after initially privately siding with the four dissenting conservative justices in wanting to strike down the individual insurance mandate.

In June, the Supreme Court ordered the case involving the citizenship question back to lower court. Roberts said there was a "significant mismatch" in Commerce Secretary Wilbur Ross's reasoning behind the case.

The Supreme Court left open the door for the Trump administration to justify the question, but the president decided to leave the question off the census for now.