In the United States, is it possible for green cards or illegal immigrants to vote as American citizens?

It is difficult in theory, but there are successful cases. However, this behavior is a serious criminal offence.

In the United States, you must first register your long-term residence address and then register as a voter. The local government has a special committee/organization responsible for review, and only those who meet the conditions can become voters. Then the list of voters will be sent to the polling station. When going to vote, the staff will check their identities, and they can vote on the list, otherwise they will not be able to enter at all.

However, according to news reports, a Mexican woman, who lives in Texas, went to vote while holding a green card to support the Democratic Party. During the application for naturalization, he was found out, and then sentenced, the green card was revoked, and he was deported.