Paul was already having difficulty making his dovish case on foreign policy to skeptical Republican voters — and then the Paris and San Bernardino attacks happened. A CNN/ORC poll conducted right before the San Bernardino shooting found that just 1 percent of those surveyed said Paul could best handle the Islamic State, and 3 percent said that Paul would make the best president on foreign policy.

“I just don’t think there are as many people in the Republican Party who share his isolationist views of the world, as he may have thought or as there were a year ago,” said the campaign manager for a rival Republican candidate who’s aligned more closely with Republican hawks. “I think that [events] have proven out that his view is incorrect.”

Then there’s money. Paul raised just $2.5 million in the most recently reported fundraising quarter — barely enough to keep the lights on, and down from $7 million in the previous quarter.

“I think the biggest indication of how Rand Paul is doing is the next fundraising report,” observed Dennehy, noting that previous reports “haven’t been great” but if the next one isn’t better, “the handwriting’s on the wall.”