Libertarian presidential nominee Gary JohnsonGary Earl JohnsonPotential GOP primary challenger: Trump's 'contempt for the American people' behind possible bid The Hill's 12:30 Report — Presented by Kidney Care Partners — Trump escalates border fight with emergency declaration Former Mass. governor takes step toward Trump primary challenge MORE insisted Monday there's "no chance" his running mate Bill Weld will leave the ticket for fear the two are taking votes from Hillary ClintonHillary Diane Rodham ClintonThorny part of obstruction of justice is proving intent, that's a job for Congress Nadler: I don't understand why Mueller didn't charge Donald Trump Jr., others in Trump Tower meeting Kellyanne Conway: Mueller didn't need to use the word 'exoneration' in report MORE that would help Donald TrumpDonald John TrumpThorny part of obstruction of justice is proving intent, that's a job for Congress Obama condemns attacks in Sri Lanka as 'an attack on humanity' Schiff rips Conway's 'display of alternative facts' on Russian election interference MORE win the White House.
"No, Bill Weld is in this for the long haul and beyond my wildest dreams Bill Weld is my running mate," Johnson said on CNN's "New Day."
"No, no chance Bill Weld drops out," he added later.
Johnson made the comments in response to CNN's Alisyn Camerota, who said there are reports that Weld, a former GOP governor of Massachusetts, is considering leaving the Libertarian ticket. She didn't attribute the reports.
"There are reports that your running mate, VP nominee Bill Weld, is considering actually dropping off the ticket because he's concerned at this point that a vote for both of you would deny Hillary Clinton a vote and therefore help elect Donald Trump," Camerota said.
Weld said in a statement to CNN on Sunday that he has no intention of dropping from the Libertarian ticket after CNN political commentator Carl Bernstein said sources told him Weld was considering dropping from the race if staying in might help elect Trump, the Republican nominee.
"Under no circumstances will our energies be diverted from our goal of winning the election and serving our country," Weld said.
"We don't think either side offers the alternative that Americans really want," Johnson told CNN on Monday, referring to Trump and Clinton.
"I think that Bill is really concerned that Hillary is going to grow government, taxes are going to go up and that there has been pay-to-play," Johnson said. 
The comments from Johnson come as the race between Clinton and Trump tightens and more Democrats worry about a repeat of the 2000 presidential election, when Green Party nominee Ralph Nader was seen as taking votes from Al GoreAlbert (Al) Arnold Gore20 years after Columbine, Dems bullish on gun reform Lobbying world 2020 Dems audition for Al Sharpton's support MORE in Florida.
Democrats are particularly worried that young voters are gravitating to Johnson and Green Party nominee Jill Stein over Clinton. 
Johnson and Stein have been performing well in polls for third-party candidates, though they appear to have little if any chance of winning the election. Both are polling less than 15 percent in polls and missed the cut for the first debate slated to be held Sept. 26 at Hofstra University, the Commission on Presidential Debates announced Friday.
Johnson has said he still thinks he can get into future debates.
"I'm polling higher right now than Ross Perot was when he was invited to do the first debate," Johnson told CNN on Monday.