More than 30,000 voters who had been registered members of the Republican Party have changed their voter registration in the weeks after a mob of pro-Trump supporters attacked the Capitol — an issue that led the House to impeach the former president for inciting the violence.

The massive wave of defections is a virtually unprecedented exodus that could spell trouble for a party that is trying to find its way after losing the presidential race and the Senate majority.

It could also represent the tip of a much larger iceberg: The 30,000 who have left the Republican Party reside in just a few states that report voter registration data, and information about voters switching between parties, on a weekly basis.