Biotech millionaire John Crowley is now close to entering the race for the Republican U.S. Senate nomination, after receiving calls from several GOP Senators, including presidential candidate John McCain, urging him to run, according to Republican sources.

Other sources said that Crowley spoke with one Republican Senate candidate, Andy Unanue, tonight and told him that he is now likely to run. Unanue has told some GOP leaders that he would withdraw from the race if Crowley gets in.

Crowley spoke at length today with Sen. John Ensign (R-NV), the Chairman of the National Republican Senatorial Committee, who urged him to run and committed resources if he does. At least five other Republican Senators also reportedly lobbied Crowley, whose efforts to find a cure for a rare genetic disease that affects two of his three children has caused Republican leaders to view the political newcomer as a potentially strong Senate candidate.

The Mercer County Republican Executive Committee voted tonight to award the line to Crowley, a Princeton resident, if he runs.  If Crowley does not run, the party voted to support Unanue over the other two candidates, State Sen. Joseph Pennacchio and Ramapo College Professor Murray Sabrin.

Earlier today, Rep. Rob Andrews said he would challenge the incumbent, Frank Lautenberg, in the Democratic primary.

Crowley, 40, announced on Monday that he would not run, citing business, military (he serves in the U.S. Army Reserves) and family commitments.

"I think the fact that Democrats and Republicans are both having contested primaries means we will have five to eight weeks of discussions of ideas that will benefit both parties," Senate Minority Leader Tom Kean, Jr. told PolitickerNJ.com tonight.