In very different ways, their two understudies provided Hillary Clinton and Donald Trump with a road map of the most productive approaches to take when the two presidential nominees renew their battle in Sunday night’s debate.

But Tuesday night’s vice presidential debate at Virginia’s Longwood University, like those of the past, will probably have little long-term impact on a presidential race in which Clinton has taken a small-but-clear lead.

Democrat Tim Kaine, eager and aggressive from the outset, pressed Clinton’s case against Trump, repeatedly quoting the GOP nominee’s most flagrant personal insults and questionable policy positions — and his refusal to release his tax returns — while seeking unsuccessfully to force Republican Mike Pence to defend him.

Pence, low-key and far calmer, sought to turn the conversation in the direction of the principal GOP argument of the need for change from the domestic and international policies of Clinton and President Barack Obama.

Though the Indiana governor indicated some policy differences with Trump, his evident preparation and unflappable manner suggested an approach that might benefit the GOP nominee if he could overcome what GOP strategist Steve Schmidt said on MSNBC was “a psychological inability to not respond to attacks.”

By contrast, Kaine’s sometimes over-caffeinated performance may have reminded Clinton there is such a thing as being too aggressive in a debate. But he probably scored points by reminding Democrats and undecided voters of the reasons for doubts about Trump’s temperament and knowledge.

Besides, Pence’s fervent defense of his opposition to abortion rights may not help Trump expand support among undecided independent and moderate Republican voters, even if he failed to mention the degree to which the Supreme Court is at stake in the election.

A CNN poll showed viewers rated Pence the winner by a small margin, though more said Kaine better defended his presidential nominee and they would vote for Clinton. Some observers speculated Pence might ultimately be the main beneficiary — if Trump loses and the Indiana governor seeks the White House in four years.

The 90-minute debate was barely 10 minutes old when Kaine noted, for the first of five times, that Trump launched his campaign by calling Mexicans “rapists and criminals,” adding “I can’t imagine how Gov. Pence can defend the insult-driven, selfish ‘me first’ style of Donald Trump.”

“Senator, you and Hillary Clinton would know a lot about an insult-driven campaign,” Pence said, bypassing for the first of many times an opportunity to defend Trump.

He did defend him when the subject of the New York developer’s massive tax write-offs came up, saying “he used the tax code just the way it’s supposed to be used. And he used it brilliantly.”

“How do you know that?” Kaine demanded. “You haven’t seen his tax returns.”

“He created a business that’s worth billions of dollars today,” Pence countered.

“How do you know that?” Kaine again asked.

Each spent some time attacking the other’s records, Pence citing tax increases passed while Kaine was governor of Virginia, and Kaine noting Pence supported a private option for Social Security while in Congress.

But the bulk of the time was spent on Clinton and Trump. During the foreign policy portion, Pence took a much harder line against Russian President Vladimir Putin, referring to the man whose leadership Trump often has praised as “the small bullying leader.”

Both displayed substantial preparation, Pence on how to parry or ignore criticism of Trump, Kaine with several obviously prepared lines, calling Pence at one point “Donald Trump’s apprentice.”

Trump’s choice of Pence helped solidify support from GOP conservatives, and Kaine may help Clinton carry Virginia. Both are veteran, experienced pols. But their overall impact seems destined to be minimal unless the race is very close.

After all, it’s been 56 years since Texas Sen. Lyndon B. Johnson was the last vice presidential running mate who clearly helped his party win a presidential race. And it’s been 42 years since Gerald Ford became the most recent of the seven vice presidents to inherit the White House in the middle of a presidential term.

Carl P. Leubsdorf is the former Washington bureau chief of the Dallas Morning News.