Of the many mistakes made in 2016 by failed Democratic nominee Hillary Clinton's campaign, arguably among the biggest was the insufficient attention paid to, resources expended in, and the taking for granted of the so-called "blue wall" of battleground Rust Belt states like Michigan, Pennsylvania, and Wisconsin.

The campaign of Vice President Kamala Harris appears determined to not make the same mistake as Clinton and is focused sharply on winning those three critical states for Democrats, according to The Guardian.

That means actually showing up to campaign in those states, talking to voters about what they want to hear -- like jobs instead of gun control -- and motivating key Democratic constituencies to cast a ballot in the upcoming election.

Clinton's grave 2016 mistake

In 2016, the nation was shocked by then-businessman Donald Trump's victory, most especially former Sec. of State Clinton and the Democratic Party, who bought in to the incorrect assumptions of her inevitability and exhibited an overconfidence that led to her unexpected loss.

Clinton's Electoral College loss hinged in large part on her loss in the three Rust Belt swing states that, for decades, typically voted for Democrats but were largely ignored and taken for granted by Clinton's campaign, according to post-election analysis from The Atlantic.

Politico later did a deep-dive into the 2016 numbers for Michigan, Pennsylvania, and Wisconsin and determined that Clinton would likely have won those states, and thus the election overall, if she had done a better job motivating working-class voters, disaffected Democratic voters, young voters, and minority voters.

A big part of that is simply showing up and being seen and saying the things those voters want to hear -- something Clinton neglected to do, particularly in Wisconsin and Michigan, in that election cycle.

Harris campaign focused on Rust Belt swing states

Per The Guardian, the Harris campaign is hoping to avoid that same mistake by placing an emphasis on the "blue wall" Rust Belt states, albeit without overcorrecting by continuing to focus attention and resources on four important Sun Belt battleground states like Arizona, Nevada, North Carolina, and Georgia.

That tracks with a leaked memo from the now-defunct Biden campaign in early July, according to the Associated Press, which mapped out multiple avenues toward victory but concluded that winning the three Rust Belt swing states was the "clearest pathway" to winning the Electoral College and a second term for President Joe Biden.

The plan likely hasn't been altered much since VP Harris succeeded Biden as the presumptive Democratic nominee after he suddenly exited the race, and The Guardian revealed that Harris has dispatched hundreds of campaign staffers to those states, is blitzing them with ads and rallies, and has enlisted the aid of Democratic governors and other influential leaders in and around the Rust Belt region.

Trump still leads in most battleground states

How that strategy ultimately plays out for VP Harris remains unknown until Election Day, of course, but the admittedly early polling suggests it may be helping her -- at least for now.

According to the RealClearPolitics average of polls, Harris currently leads former President Trump nationwide by a half-point, 47.4-46.9%, though polls at the state level offer mixed results.

In Wisconsin, Harris is also up by 0.5 points over Trump while her lead in Michigan stands at 2.0 points, yet she trails the former president in Pennsylvania by a 1.8 point margin.

Harris will have her work cut out for her in the non-Rust Belt swing states, though, as RCP currently shows Trump leading in Arizona by 2.8 points, Nevada by 4.0 points, North Carolina by 3.0 points, and Georgia by 0.8 points.