It is currently a civil violation of immigration law for someone to overstay their visa, or to enter the US without adequate documents; this is not a part of the Federal criminal code.
OK, let us make it a Federal Felony.
It is legal to shoot a fleeing felon.
She should be careful what she wishes for.
It is not (currently) a criminal offense to enter the U.S. legally and then overstay your visa (illegal presence). You are still an illegal alien, but your unlawful presence is a civil offense.
It is a criminal offense to enter the U.S. illegally (illegal entry). It is also a criminal offense to use fraudulent documents to enter the U.S., or to get a job, collect welfare, vote, etc.
"Any alien who (1) enters or attempts to enter the United States at any time or place other than as designated by immigration officers, or (2) eludes examination or inspection by immigration officers, or (3) attempts to enter or obtains entry to the United States by a willfully false or misleading representation or the willful concealment of a material fact, shall, for the first commission of any such offense, be fined under title 18 or imprisoned not more than 6 months, or both, and, for a subsequent commission of any such offense, be fined under title 18, or imprisoned not more than 2 years, or both."