According to a new online poll conducted by a number of veterans advocacy groups and military-related websites, Libertarian nominee Gary Johnson is the most popular presidential candidate among active military members and veterans, with about 53 percent support, far ahead of the 20 percent each garnered by Donald Trump and Hillary Clinton.

But the poll — sponsored by Military OneClick, Got Your 6, We Are The Mighty, and Doctrine Man — is hardly foolproof. The 1,399 respondents who self-identified as active military, veterans, or military family members were not verified in any way. Also, because this latest military poll is an "opt-in" poll, its results can be skewed depending on how and where the poll was promoted, among many other variables.

According to a representative with Got Your 6, the poll was conducted using SurveyMonkey, which imposes a limit of 1 vote per device and IP address. So, technically a person could vote repeatedly by clearing their cache or using multiple devices, but any attempts at poll-stuffing wouldn't be as simple as merely voting over and over again.

Angie Drake, a volunteer with Doctrine Man, told Reason that "active duty military are not allowed to publicly support candidates or political parties" and requiring a valid email address or other identifying information would have "compromised participation" in the polling and put participants at risk.

Online polling, as opposed to other randomized methods of polling, also presents challenges. The Washington Post recently explained its use of SurveyMonkey in taking a national poll of American voter attitudes:

While standard Washington Post surveys draw random samples of cellular and landline users to ensure every voter has a chance of being selected, the probability of any given voter being invited to a SurveyMonkey is unknown, and those who do not use the platform do not have a chance of being selected. A margin of sampling error is not calculated for SurveyMonkey results, since this is a statistical property only applicable to randomly sampled surveys.

During the run-up to last week's "Commander in Chief Forum" broadcast by NBC and hosted by Iraq and Afghanistan Veterans of America (IAVA), a previous Doctrine Man poll — which showed Johnson leading among active military — was frequently cited by his supporters to advocate for his inclusion in the forum alongside Donald Trump and Hillary Clinton. Responding to complaints over Johnson's exclusion on Twitter, IAVA CEO Paul Rieckhoff cited a Military Times poll putting Johnson in third place among military, implying he believed this Military Times poll to be more accurate.

But a new poll currently being conducted by Miliary Times and Syracuse University suffers from the some compromises as the Military OneClick (et al) poll. Though the poll is intended to be limited to active military, veterans, and their families, no verification or valid email address is required. I took the poll myself (as the family member of an active military serviceperson) and found that I could immediately take the poll again afterward. No change of device, IP address, or even browser was required.

So is Gary Johnson really winning the vote of active military members? Hard to say, though it wouldn't be shocking if he were. In 2012, libertarian hero Rep. Ron Paul (R-Texas) dominated the GOP presidential field when it came to racking up donations from active military.

But because even the margin of error in an opt-in online poll can't be determined, and because of the limits on political speech imposed on active military, all of these polls claiming to be a definitive view into the political preferences of the military rank-and-file should be taken with a grain of salt.