A new poll shows Democratic Rep. Bruce Braley leading the opening Iowa Senate race against all of his potential GOP opponents, but the race remains competitive.

The Quinnipiac University poll shows Braley leading former U.S. Attorney Matt Whitaker 43-40, state Sen. Jodi Ernst 44-38, and businessman Mark Jacobs 46-37.

Whitaker, Ernst and Jacobs are part of a crowded field of lesser-known candidates vying to face Braley.

Despite their deficits, the poll shows Iowa voters would prefer a GOP-controlled Senate to a Democratic one by a margin of 46-41. That suggests that, as people become more familiar with these GOP candidates, their share of the vote could rise.

Iowa is generally considered a second-tier target for Republicans, behind a number of red states that are currently controlled by Democrats.

If Republicans win in Iowa, the new senator would likely be part of a new GOP majority, as the party will likely have won a number of red states as well.