Alternative to 53-Across

ROTH

Think of a retirement account named after a senator that starts with R.

This clue hints at a type of retirement account that serves as an alternative to the one named in 53-Across (likely a "traditional IRA"). "ROTH" refers to a Roth IRA, a tax-advantaged savings plan where contributions are made after taxes, unlike its traditional counterpart. The wordplay is straightforward—it’s a direct comparison between two common IRA options. If 53-Across is "IRA," then "ROTH" neatly fills in as the other well-known choice.