A new national poll shows sliding support for Hillary Clinton, and reason for Republicans to worry about other potential Democratic nominees.

FOX News Radio's Jared Halpern has more from Washington:

Hillary Clinton still tops the Democratic field in the latest Quinnipiac University national poll with 45% but that is down from 55% a month ago. Senator Bernie Sanders is behind with 22%.

Clinton also edges out the top Republican candidates in potential head-to-heads, but does not run as well against the man not in the race... Vice President Joe Biden.

The survey shows Biden tops Republican front-runner Donald Trump by eight points. He also would beat Jeb Bush and Marco Rubio.

Sanders, the poll finds, edges Trump and Bush, but runs neck-and-neck with Rubio.

In Washington, Jared Halpern, FOX News Radio.