WASHINGTON — As President Donald Trump and former Vice President Joe Biden prepared for the equivalent of high-profile trench warfare on the political battlefield of Iowa on Tuesday, a third 2020 candidate found the high-ground vantage point he needed to strike both of them at the same time.

South Bend, Indiana, Mayor Pete Buttigieg, a veteran of the war in Afghanistan who hopes to defeat Biden and almost two dozen other Democrats for his party's nomination and then oust Trump from the Oval Office, delivered a wide-ranging foreign policy and national security speech with a simple point: the United States would be hopelessly stuck in the past with either the president or the former vice president at the helm.

He didn't have to name his targets, neither of whom served in the military, to hit them.

"Faced with this moment of great challenge and possibility, it’s not enough just to say we won’t conduct foreign policy by tweet," Buttigieg said at Indiana University in Bloomington. "Nor would it be honest to promise that we can restore an old order that cannot, in any case, meet the realities of a new moment. Democrats can no more turn the clock back to the 1990s than Republicans can return us to the 1950s."

Biden, who began his service on the Senate Foreign Relations Committee in 1975, was the top Democrat on the panel for the latter part of the 1990s, later serving as its chairman.

What it amounted to Tuesday was a little bit more of a triptych than the split-screen imagery hoped for by Biden and Trump, another data point in a trend of Democratic candidates starting to paint the two front-runners in the similar — fading — hues of yesterday's news.

Trump and Biden, who spent parts of the day exchanging insults, are treating each other as the main combatants in the fight for the presidency.

Trump has no real competition for re-nomination, and Biden, despite a couple of missteps and slippage in recent polls, remains the leader of the pack for the Democratic nod. He has steadfastly avoided criticizing his Democratic rivals, preferring to run a campaign focused on the idea that Trump is the only obstacle in his path to the presidency.

Early excerpts of remarks Biden planned to deliver Tuesday night in Davenport, Iowa, were a full-on assault on Trump's presidency, his character and his competence.

"America's farmers have been crushed by his tariff war with China," Biden was expected to say. "No one knows that better than Iowa. He thinks he's being tough. Well, it's easy to be tough when someone else is feeling the pain. ... How many sleepless nights do you think Trump has had over what he's doing to America's farmers?"

In addition to trade, Biden planned to go after Trump on climate change, income inequality, his response to the fatal clash between white nationalists and counterprotesters in Charlottesville, Virginia, in 2017, and policy at the U.S.-Mexico border.

"This isn't who we are," Biden will say, according to the excerpts released by his campaign. "We hold these truths self-evident — that all men — and all women — are created equal. It's the American creed. But Trump sneers at it. He thinks it makes us weak. He has no idea it's what makes us strong."

Before departing for Iowa, Trump called Biden a "loser" and said he didn't think much of the former vice president's brainpower, verve or chances of winning the Democratic nomination.

"I'd rather run against, I think, Biden than anybody," Trump said. "I think he is the weakest mentally. I like running against people that are weak mentally. I think Joe is the weakest up here. The other ones have much more energy."

He also said of Biden that "it looks like his friends from the left are going to overtake him pretty soon."

With many Democratic voters viewing Biden as their best shot to tackle Trump, fellow Democrats have been somewhat reluctant to risk a backlash by taking shots at the former vice president. Despite a contentious 2008 Democratic primary leading to a party victory in that year's general election, the experience of losing in 2016 after a rough primary fight has made many Democratic voters wary of negativity in their own ranks.

But in recent days, after a long honeymoon period for Biden in which his poll numbers soared following his April launch, his Democratic rivals are starting to become more comfortable making the case that his brand of politics — more centrist and less disruptive than much of the field — isn't the right solution for the party or the country.

Enter Buttigieg on Tuesday.

His critique of modern foreign policy included a call to repeal the 2001 Authorization for Use of Military Force in Afghanistan that underpins the continued U.S. presence in that country and was used by President Barack Obama's administration — the one in which Biden served as vice president — as well as a vow to pull funding from Israel if it expands into Palestinian areas.

"If Prime Minister [Benjamin] Netanyahu makes good on his promise to annex West Bank settlements, he should know that a President Buttigieg would take steps to ensure that American taxpayers won't help foot the bill," he said.

Trump has applauded Israeli settlements and recognized Israel's claim to the Golan Heights region, while Biden, who much earlier in his career reportedly talked about cutting U.S. aid to Israel over expansion, did not repeat that threat when he condemned Israel's announcement of new settlements while he was visiting the country in Obama's first term.

Buttigieg is hardly alone in wanting to repeal the 2001 AUMF and replace it with something much more limited. All of the senators seeking the Democratic nomination voted in 2017 against killing an amendment by Sen. Rand Paul, R-Ky., that would have repealed both that authorization and the one that covered the U.S. invasion of Iraq, and given lawmakers six months to draft a replacement.

But as often happens in the midst of a presidential campaign, the calendar, the moment in time and a candidate's message conspired to create an opportunity.

In this case, it was the mayor of a small Midwestern town taking advantage of a slugfest between two titans with top-level foreign policy experience to try to make his vision for national security seem bigger — "to master change rather than be made small and fearful by it."