• Trump-endorsed Dr. Oz is in the midst of a tight GOP primary, with opponents using fame against him.
• Lt. Gov. John Fetterman has nearly a 40-point lead on U.S. Rep. Conor Lamb in the latest poll.
• In some cases, voters see celebrities as more credible than politicians, one analyst said.
• Fetterman has 200,000 individual donors, the most by far in the U.S. Senate race in Pa.

WASHINGTON – When Donald Trump talks about why Dr. Mehmet Oz should be a United States senator, he cites Oz’s medical background, his conservative views – and, above all, something else.

His celebrity.

“His show is great,” Trump told supporters at a May 6 rally in Pennsylvania, site of a Tuesday primary that showcases a powerful development of 20th and 21st Century public life: celebrity politics.