Rep. Ilhan Omar (D-Minn.). Photo: Leopaltik1242/Wikimedia Commons.

The bipartisan coalition in American politics in support of Israel since 1948 has been a blessing for the Jewish state — and sometimes even a necessity, as during the 1967 and 1973 wars.

But pious declarations that American Jews should remain united (when they are increasingly divided) in support of bipartisanship on Israel (which according to the polls is fast fading) are no substitute for political realism.

The US has long been a two-party country, with most voters slightly to the right and left of center, and the winning party taking more than 50 percent of the vote. But things have not always been that way. Lincoln won in a splintered political field in 1860 with just over 40 percent. Woodrow Wilson won a three-cornered race in 1912 with the same amount. And thanks to George Wallace, Richard Nixon won in 1968 with under 50 percent.

Just as the cable television revolution fractured the monopoly of the big three TV networks, there is reason to believe that multi-factional polarization may make it increasingly difficult for future presidents to get over 50 percent of the vote, much less win in presidential landslides.

This means that there are now two ways to win American national elections: the traditional way, by reaching out to the center and forming a majority; and the new way of “winning by dividing” — solidifying your own base while finding ways to fragment or factionalize the other party or parties.

Indeed, intentionally or not, this is how Donald Trump won in 2016 with solid GOP support, but with two minor parties also competing that took away just enough votes from Hillary Clinton to defeat her.

And what are the implications of this new “win by dividing” reality for American Jewish voters, especially those who support Israel? Currently, about one in four Jewish voters — overwhelmingly pro-Israel — vote solidly Republican, while three in four are Democratic mainstays. But these people are less solidly Democratic, and also less solidly pro-Israel because of defections among younger voters.

Much of the criticism of Congresswoman Ilhan Omar and her allies, Congresswomen Tlaib and Ocasio-Cortez, is morally sound but politically on shaky ground.

We must ask what Omar is really doing by stigmatizing Jewish voters as corrupt money-manipulators more loyal to Israel than the US.

Omar’s defenders and apologists argue that she is just using sometimes ill-chosen words to criticize Israel. But the truth may be the opposite. Her real target may be American Jewish voters, not because they support “right-wing” Israeli governments (which isn’t true), but in order to reduce their power in the Democratic Party — even driving them out of it — to give a stranglehold on the party to a “progressive” coalition of people who are either antisemitic or indifferent to antisemitism.

Why would Omar’s “progressive” faction do this, despite the probability that it would cost their party some Jewish votes and Jewish political contributors? The reason is that in politics today, victory can come from control of a unified, almost cult-like party that can win elections by keeping the other parties divided. This is exactly what Donald Trump did in 2016.

So what should American Jewish voters do? Not necessarily give up on the Democrats and jump en masse to the GOP, but they must learn that efforts to placate the far left won’t work — and are likely counterproductive.

Historian Harold Brackman is coauthor with Ephraim Isaac of From Abraham to Obama: A History of Jews, Africans, African Americans (Africa World Press. 2015).