When it comes to political mistakes, Sen. Elizabeth Warren, D-Mass. – a likely candidate for the 2020 Democratic presidential nomination – just made a doozy. President Trump wasted no time drawing more attention to Warren’s foolish move with two stinging tweets Tuesday.

On Monday, Warren announced that she had taken a DNA test to prove her Native American ancestry. This was her attempt to strike back against President Trump and others who have long questioned her assertion that she has Cherokee heritage.

Unfortunately for Warren, the DNA results did little to advance her cause – in fact, the trace amount of Native American DNA that Warren apparently has makes her claim to having American Indian ancestors look laughable.

It appears Warren has less Native American DNA than the average American of European descent. And in any case, her DNA was not compared to any actual tribes – Cherokee or otherwise – but rather a mix of Mexicans, Peruvians, and Colombians.

For some bizarre reason, Warren thought she could spin this fiasco in her favor and create a political winner because one test found that hundreds of years ago there was a Native American ancestor on her family tree.

President Trump tweeted Tuesday: “Now that her claims of being of Indian heritage have turned out to be a scam and a lie, Elizabeth Warren should apologize for perpetrating this fraud against the American Public. Harvard called her ‘a person of color’ (amazing con), and would not have taken her otherwise!”

The president also tweeted: “Thank you to the Cherokee Nation for revealing that Elizabeth Warren, sometimes referred to as Pocahontas, is a complete and total Fraud!”

On Monday, Cherokee Nation Secretary of State Chuck Hoskin Jr. said that “a DNA test is useless to determine tribal citizenship” in the Cherokee Nation. “Current DNA tests do not even distinguish whether a person’s ancestors were indigenous to North or South America.”

What’s most astonishing is the timing of Warren announcing her DNA test results. By launching this salvo just three weeks before the midterm elections, Warren made a misguided bet that her story would somehow be a boon for the Democratic Party.

The odds of that happening are slim, of course. Bookies might put it at somewhere around 1 in 1,024 – or the same tiny fraction of Warren’s DNA that could come from a Native American ancestor six to 10 generation earlier, according the Warren’s DNA test.

That works out to as little of .09 percent of Warren’s DNA coming from a Native American ancestor – an insignificant factor.

Already, the media are filled with news stories and debates about what the results of Warren’s DNA test actually mean. At some point, reporters will come to understand how silly it is to use these tests to determine one’s ethnicity or race.

Case in point: Christine Willmsen, a white reporter or The Seattle Times, recently had her saliva tested by two companies – DNA Diagnostics Center and Ancestry.com.

“According to the results, which are estimates, I am 87 percent Caucasian and 13 percent sub-Saharan African,” Willmsen wrote of the DNA Diagnostics Center test. That left her and her family quite surprised, she wrote. They never had any inkling that they had black ancestors.

But then Ancestry.com test results “claimed I am 100 percent Caucasian” Willmsen wrote.

These contradictory reports obviously can’t both be right.

The only thing we can conclude is that Warren’s test means very little because the underlying science used by these testing services is at best highly questionable, and at worst largely garbage.

It’s possible that a different DNA test might come up with completely different results on Warren’s ancestry, as the two tests did for Willmsen.

The bottom line is that Warren has given Republicans a tremendous political gift heading toward the Nov. 6 midterm elections.

First, the media are rightfully resurrecting stories of the senator changing her ethnicity from white to Native American – first at the University of Pennsylvania in 1987, then at Harvard University in 1995.

The ethnicity switch by Warren seems to have been an attempt to get favorable consideration as a member of a minority who could be helped by affirmative action programs – although she denies that’s the case. But why else would a person who had always described herself as white suddenly identify herself as a Native American?

This focus on Warren’s DNA takes attention away from attempts by Democrats to get news coverage for their attacks on GOP candidates for supporting President Trump on a broad range of his policies. This diversion could hurt efforts by Democrats to gain majority control of the U.S. House and Senate in the midterm elections.

Bringing renewed media attention to America’s culture wars, including the embrace by liberals of identity politics and affirmative action in higher education and elsewhere, is a losing proposition for Democrats.

Instead of being judged by our performance and hard work, too many Democratic candidates want to put each of us into a box based on our race, ethnicity or gender – factors that are all completely out of our control. That may win them support on the far left but hurts them with the swing voters who will decide the outcome of close races Nov. 6.

Polls show most voters don’t support affirmative action – especially for college admissions. Indeed, most voters backed President Trump’s action in July that reversed policies by President Obama that encouraged colleges and universities to consider a student’s race in college admissions to promote diversity.

Warren’s debacle thus gives Trump and the Republicans a key political opening. Watch for the GOP to highlight examples of progressives pitting one group of people against another, like the blockbuster allegations against Harvard University that it discriminates against Asian-Americans in order to benefit other, more preferred minorities.

The message writes itself: A vote for Democrats is a vote for division and discrimination.

The real question is whether voters will buy the argument. Odds are that staunch Democrats won’t be moved to pull their support from the party. But Republicans and independents are likely to be different – especially those who’ve been disadvantaged by affirmative action.

Warren could turn out to be an important driver of the GOTV (get out the vote) effort – for Republicans.

Regardless, one thing’s clear: Warren’s goal of putting all this Cherokee mess behind her has utterly backfired. Rather than show herself to be a steady leader with careful strategy and political moxie, she will be forever remembered as the teller of ethnic half-truths and family folklore in search of political power.

And you don’t need a DNA test to see that.