Libertarian presidential nominee Gary Johnson is escalating his criticism of the major-party candidates as he attempts to qualify for the first presidential debate on Sept. 26. He should be taken seriously. His credibility is rising; he is attracting more media attention by the day, and he has plenty of serious ideas that undergird his campaign.

Johnson actually has a decent chance to get into that first debate in Hempstead, New York. This is partly because the major-party nominees are so unpopular, and Johnson is seen as a respectable alternative. Fifty-seven percent of likely voters have an unfavorable view of Republican nominee Donald Trump, and 51 percent have an unfavorable view of Democratic nominee Hillary Clinton, according to the latest Monmouth University poll.

A candidate will need at least 15 percent support in the polls to qualify for the debate. The Monmouth survey voters give Clinton 46 percent, Trump 39 percent, Johnson 7 and Green Party candidate Jill Stein 2. The latest NBC News/Survey Monkey poll, released Tuesday, gives Clinton 41 percent, Trump 37, Johnson 11 and Stein 5. Johnson needs to gain only a few percentage points to vault into the debate, which is vital to his prospects.

Johnson brims with optimism. "You know how crazy this election cycle is," Johnson told Fox News this week. "I might be the next president!" This borders on the impossible. The last independent or third-party candidate to do really well in a presidential election was businessman Ross Perot in 1992. He got 19 percent of the vote but didn't carry a single state.

Still, Johnson is making some powerful arguments. He says Trump is an authoritarian who has little regard for the Constitution. Asked by The New York Times if he considered Trump a fascist, Johnson said he did. "It walks like a duck, quacks like a duck," Johnson said. "Where's the Constitution in all this?" Johnson added: "He's saying horrible things."

Johnson, the former two-term GOP governor of New Mexico, also told CNN that Clinton, as secretary of state, was wrong to give special government access to donors to her family's Clinton Foundation. Johnson said there was an "implication" of a "pay to play" arrangement. He said, however, that he did not consider the arrangement illegal.

He seems to be trying to attract mainly GOP votes, and that's probably where he has the most potential for increasing his support. Johnson told The New Yorker Radio Hour in an interview released this week, "I think this is the demise of the Republican Party....Donald Trump alienates more than half of Republicans." He added: "I think most Republicans are about small government...and really that's just been co-opted." Johnson said, "Donald Trump seems to be all over the board in regard to everything....Building a wall across the border, that's crazy....Killing the families of Muslim terrorists, that's crazy....Tariff on imported goods, who's going to pay for that? ...It just goes on and on."

Johnson has an average of about 9 percent support in national polls, according to FiveThirtyEight, a political research organization. The group points out that his share has not fallen in recent weeks, as tends to happen to third-party candidates at this point in a presidential cycle. "Indeed, Johnson's support right now is higher than many other viable third-party candidates at a similar point in campaigns since 1948," the group said.

"Why is Johnson's support proving more durable than past third-party candidates'?" the analysis asks. "The most obvious answer is that Donald Trump and Hillary Clinton are extremely unpopular for major party presidential nominees; if third-party voters eventually settled on a major party nominee in past campaigns for fear of 'wasting their vote,' they may be less willing to settle this year. (Of course, Johnson's support may simply fade later than past third-party candidates)."

Johnson said that even if he doesn't win the White House, he expects to make history by hastening the end of the Republican Party and helping to build the Libertarians into a major force. "That's going to be the consequence of what we do, at a minimum," Johnson told the Times. He says the GOP is adopting policies that are too meddlesome in people's lives, and he supports individual choice on abortion, same-sex marriage and use of marijuana, which he wants to legalize. He also breaks with many Republicans because he opposes the phasing out of Social Security and instead supports cost-saving changes in the retirement system, such as raising the retirement age to 72. He bills himself as a non-interventionist in foreign policy, another departure from many Republicans who favor an active U.S. role abroad, including the use of the military in some cases. Johnson's other policy stands include eliminating the income tax and the corporate tax and replacing them with a federal consumption tax. Johnson describes himself as a fiscal conservative and a social liberal.

It's not outside the realm of possibility that Johnson could spoil the major-party candidates' chances in a handful of states. He already is doing particularly well in Colorado, New Hampshire and Utah.