() Republicans in Congress have reintroduced the Safeguard American Voter Eligibility (SAVE) Act, and experts are warning the law could make it harder for many Americans to vote.

What is the SAVE Act?

The proposed law would require Americans to prove their citizenship status by presenting specific documentation in person when they register to vote or update their voter registration.

Specifically, the law would require certain documents that comply with REAL ID laws to be presented, generally a birth certificate, naturalization certificate or passport.

Roughly half of Americans do not have a valid passport. For those who don’t have a copy of their birth certificate on hand, getting a copy can take time and require paying a fee.

How would the SAVE Act change voter registration?

Driver’s licenses, which have traditionally been used to register voters, would no longer be valid. Neither would state ID cards issued to people who can’t or don’t want to drive but still need ID. That would be true even if the license conforms to REAL ID standards.

Military or tribal IDs would also be invalid for voter registration.

The documentation would also have to be given in person, which would mean an end to voter registration by mail, online voter registration and voter registration drives.

How would the SAVE Act affect married women?

To register, the required documents would need to match the voter’s current legal name.

For married women who take their spouse’s name (or husbands who do the same), this could present a problem if they lack a passport. When someone changes their name after getting married, they are not issued a new birth certificate.

The law doesn’t outright prohibit people whose names don’t match from registering, but they would be required to provide additional documentation, like a marriage license, which would create more barriers to registering.

How would the SAVE Act affect college students?

The law would require documents to be presented in person for registration and changes, like updating a mailing address. Many young people may not have access to the documents they need.

For college students who attend school in a different city or state, this would remove the option to update their registration online or by mail and require them to travel back home to make any changes.

How would the SAVE Act affect transgender Americans?

Transgender voters could also face barriers to registering because many states do not allow them to get a new birth certificate with their updated name and gender. As with married women, trans people would have to provide additional legal documentation of a name change to register.

The Trump administration has made changes that prohibit people from changing their gender on passports, making it harder for trans people to get one form of suitable ID, and some trans people have reported they are unable to get a passport at all.

How would the SAVE Act affect rural voters?

Millions of Americans who live in rural areas and rely on mail or online registration would have to register in person, potentially requiring long drives to register.

That would also affect elderly voters who are unable to drive and live in rural areas with little public transportation.

Service members who rely on the ability to register or update registration by mail while deployed would also face difficulty registering to vote under the new law.

How would the SAVE Act affect low-income Americans?

The SAVE Act requires documents many Americans don’t have on hand. Obtaining a passport or birth certificate are both processes that cost money, which creates barriers for low-income Americans who can’t afford those fees.