Does the Constitution Have 27 or 28 Amendments Now?

As President Joe Biden prepares to announce his pick to put the first black woman on the Supreme Court, one question is sure to arise in her confirmation hearings: How many amendments are there to the Constitution?
It may seem like a question better suited for a high school government class, but the answer isn’t as obvious as it seems.
Last week, Biden urged Congress “to pass a resolution recognizing ratification of the ERA” as the 28th Amendment to the Constitution. The Equal Rights Amendment, he argued, would “definitively enshrine the principle of gender equality in the Constitution.”
The ERA was drafted by women’s rights activist Alice Paul in 1943: