Like the proverbial general who is always ready to fight the last war, Rhode Island Gov. Lincoln Chafee charged screaming into the 2016 fray wielding obsolete hardware.

“I don’t think anybody should be president of the United States that made that mistake,” Chafee said of Hillary Clinton’s 2002 vote in favor of the authorization to use force in Iraq. “It’s a huge mistake and we live with broad, broad ramifications today — of instability not only in the Middle East but far beyond and the loss of American credibility. There were no weapons of mass destruction.”

For a campaign that has a reputation for nipping problems like Chafee in the bud, the fact that his comments went largely ignored by Clinton’s vast network of character assassins was odd. Even the virtually unknown former Sen. Jim Webb was the target of a Team Hillary smear campaign when he entered the race against Her Inevitableness. So, why did Clinton’s apparatchiki simply disregard Chafee? Perhaps because his opening volley fell so wide of the mark.

The results of a recent YouGov poll are perhaps instructive on why Hillary Clinton and her allies no longer fear the attacks on her record as a senator that proved so devastating in 2008. That survey found that only 15 percent of voters polled believe that having supported the 2003 Iraq War is a “totally unacceptable” policy position. Unsurprisingly, only 4 percent of self-described Republicans believe that a candidate’s support for the Iraq War is a nonstarter, but a shockingly low number of Democrats, 19 percent, agree.

That poll also found that Americans have fully recovered from the post-Iraq War hangover. 48 percent of those surveyed expressed some level of support for committing ground troops to the fight against the Islamic State in Iraq and Syria while 41 percent disagreed. Only 23 percent of self-identified Democrats said it was “totally unacceptable” for a presidential candidate to support the reintroduction of ground forces into the Middle East.

YouGov found that a candidate’s position on the issue of climate change is far more important to both Democrats and, though to a much lesser extent, the general electorate. A full 60 percent of respondents said that it was either “totally” or “mostly unacceptable” for a candidate to express doubts about the nature of anthropogenic climate change. Just 6 percent of Republicans agree with this statement while 54 percent of Democrats believe heresy on the issue of global warming is a disqualifier.

In January, I noted that the coming Democratic primary would likely hinge on the issue of global warming. Beyond “income inequality,” no other issue so animates the Democratic electorate. Moreover, it is an issue that has been evolving into a top priority for Democrats and Democratic-leaning voters at a rapid pace.

That phenomenon is evident in comments from prominent Democrats who remain popular with their party’s grassroots despite their support for the Iraq War.

Climate change absolutism is what compelled Secretary of State John Kerry to insist that he had both organized and attended the first congressional hearing on the issue of climate change when he had done neither. Dogmatism on the issue of global warming led Hillary Clinton to declare the Obama administration’s increasingly onerous regulatory burden on the economy the single most important acts of his presidency. “As you know so well, power plants account for about 40 percent of the carbon pollution in the United States, and therefore must be addressed,” Clinton said in December. “And the unprecedented action that President Obama has taken must be protected at all cost.”

If there is an issue that could relieve Clinton of her status as Democratic frontrunner, it is no longer the Iraq War. Only the issues of climate change and radical income redistribution have the capacity to derail her quest for the nomination. While she is no doubt weak on the latter, Clinton has done a fair job of insulating herself against attacks from her left on the former.