Kentucky Secretary of State Trey Grayson's (R) Senate campaign has released a poll showing his primary with Rand Paul is a tie.

The Voter/Consumer Research poll shows each candidate at 40 percent, with 20 percent of voters undecided. Six hundred likely primary voters were surveyed on Wednesday and Thursday,

The poll does not include crosstabs detailing either candidates strengths, and it did not include any of the minor candidates, who took a combined 6 percent in a recent SurveyUSA poll.

Pollster Jan van Lohuizen points out that both Grayson and Paul have similar name recognition and favorability numbers. But the numbers are not provided.

That Grayson needs to release a poll showing him tied with Paul shows that Grayson's campaign feels the need to assure donors that the race is competitive. Paul has shown a wide lead in other recent polling, and Grayson's campaign is dealing today with Dr. James Dobson switching his endorsement, which he originally made last week, from Grayson to Paul.

The primary is May 18.

Update 12:15 p.m.: Paul campaign manager David Adams responds: "No one, at this point, expects anything but a big Rand Paul lead based on his support for balanced budgets, term limits, a pro-life and pro-family agenda and a strong national defense."