You gotta hate Congressman Steny Hoyer. In a few lines delivered at the AIPAC Policy Conference, he ruined so many popular narratives.Actually, just by showing up, the House Majority leader with a 95% rating from the liberal Americans for Democratic Action proved that liberal Democrats aren’t abandoning Israel, and that AIPAC’s big tent remains broad and welcoming.When he said, “I am not Jewish, nor do I do represent a large Jewish constituency, but I have visited Israel some 15 times, and I have seen the courage of its people and their enduring spirit to make their country flourish,” he proved that you don’t have to be Jewish – or bribed by lobbyists – to be pro-Israel.When he said, “When someone accuses American supporters of Israel of dual loyalty, I say: Accuse me,” and that “I am part of a large, bipartisan coalition in Congress supporting Israel; I tell Israel’s detractors: Accuse us,” he proved that supporting Israel and fighting antisemitism are all-American issues.When he demanded, “Let’s have debates on policy instead of impugning the loyalty of Israel’s supporters,” he showed that some Washington politicians still focus on substance, not sneering.And when he ad-libbed a line that “there are 62 freshman Democrats – you hear me? Sixty-two, not three,” he really made a mess, showing that the Democratic Party may not be veering as left as all the fanatics in Twitterdumb – from the Left and the Right – want us to believe.As a historian, I feel badly for my pollster friends. I take solace from today’s traumas by reading about yesterday’s horrors. But pollsters keep showing that most American Jews remain pro-Israel, most young Jews remain pro-Israel, most Americans remain pro-Israel, most Democrats remain pro-Israel – yet they keep getting ignored.Yes, radical liars from IfNotNow, a marginal group that trains some young misanthropes to push their anti-Zionist agenda by sneaking onto Birthright buses or Jewish camp staffs, exaggerate their popularity.Typically, they released a press release claiming: “Young Jews rally to denounce the alliance between Benjamin Netanyahu and Donald Trump.” It implied a “young Jews’” consensus, when they cannot compete numerically (or morally) with the 4,000 students who attended AIPAC.And yes, clever Republicans and radical Democrats want to make “the three” Hoyer attacked – Ilhan Omar, Alexandria Ocasio-Cortez, and Rashida Tlaib – the voice of the Democratic Party. Exaggerating their importance helps Republicans caricature Democrats as beyond the American consensus, and helps radical Democrats pretend they reflect their party, not an alienated, angry minority. HERE, THEN, is the real challenge Hoyer tackled. The fight over AIPAC is not just about the truths regarding that organization and the American-Israel relationship. Yes, many progressives attend the policy conference, which features sessions about progressive Zionism and receptions for “peace builders,” “women in leadership” and the like. Yes, the bipartisan support for Israel is not just America’s gift to Israel but Israel’s gift to America – healthy democracies need some issues on which Left and Right agree. And yes, AIPAC represents grassroots support, not gold-plated Astroturf. Meghan McCain of The View proclaimed: “Americans don’t support Israel because AIPAC is influential. AIPAC is influential because Americans support Israel.”But this fight runs deeper. It’s about truth and the true nature of American politics in the Internet age. Twitterdom is Twitterdumb because it’s foolish to believe the shouting on Twitter reflects the kind of discourse Americans want or the opinions they hold. The ABCs of politics-by-tweet – the anonymity, brevity and crudity – bring out the political beast in us, radicalizing our politics, coarsening our culture. It’s a hall of mirrors. The tweets’ harshness, Left and Right, feed off one another, escalating, radicalizing, polarizing our politics. And reporters now take Twitter wars so seriously they quote tweets while running screenshots of the various tweets.True, America’s President Donald Trump won the presidency tweet by tweet, and governs 240 characters at a time, too. Inevitably, this punchline president has proved to be coarse and divisive. It’s a match made in hell: Trump was made for the medium, and the medium was made for Trump.“The three” mimic Trump. Many Americans have probably heard of AOC, who was born in 1989, more than they have of Hoyer, who has served in Congress since 1981 – but we rely on Hoyer! And, so far, most Democratic presidential candidates seem bullied by Twitterdumb into taking more radical positions than most Americans.Here’s where AIPAC can save America, not just support Israel. As a big-tent, bipartisan centrist movement with clear redlines against bigotry and for democracy, it must help revive the American Center. Its success should be a model to Americans not to let Twitter-shaming, Right or Left, yank the conversation to whatever extreme you might occasionally flirt with but ultimately know to avoid. AIPAC members should flex their democratic muscles in the invisible primary – the preprimary presidential race – shutting out any candidate who doesn’t condemn antisemitism clearly, support Israel passionately, practice civility consistently and defend American values aggressively.Of course, AIPAC must avoid mission creep. Its focus should remain on preserving the American-Israel relationship. But by mobilizing the silent majority, the civil Center, the constructive patriot, it should help prove that just as ugliness in Twitterdumb is infectious, the kind of constructive patriotism I heard from Hoyer and encountered repeatedly at the AIPAC Policy Conference – from Republicans and Democrats, Jews and non-Jews, united by their love of Israel – can be just as catchy, and redemptive, too.The writer is the author of The Zionist Ideas, an update and expansion of Arthur Hertzberg’s classic anthology, The Zionist Idea, published by the Jewish Publication Society. A distinguished scholar of North American history at McGill University, he is the author of 10 books on American history, including The Age of Clinton: America in the 1990s.