Originally Posted by jsloan

The Minimum Connection Time at EWR for a UA-UA transfer without a change of terminal is 30 minutes. That doesn't mean you're likely to make your flight -- you're not, unless everything goes perfectly -- just that UA will rebook you if you misconnect.

If you do miss your flight, you can ask for the nonstop instead of a connecting flight; without asking, which one you'd get depends more on the agent than anything else. As you say, though, there's no guarantee that there will be a seat available on EWR-LAX the next day.

UA isn't under any particular obligation to rebook you, although if you ask nicely you may find a willing agent. On the day of departure, you can do a same-day confirmed change for $75 (anecdotally, that fee may be waived for *G, but it's not an official benefit) -- but that requires inventory to change into. Alternatively, you can stand by for an earlier DCA-EWR flight. You're likely to end up in coach if you do so, but at least you'll get to EWR in time for your flight.