WASHINGTON — Higher walls and a half-dozen extra guards couldn’t have stopped the Sept. 11 assault by scores of attackers on the U.S. Consulate in Benghazi that left the U.S. ambassador to Libya and three other Americans dead, the State Department’s former security chief for Libya told Congress Wednesday.

Sparring and angry questioning of witnesses underscored how the deaths of Ambassador Christopher Stevens, a State Department computer expert and two U.S. security contractors — and the Obama administration’s response to them — have become issues in presidential and congressional races.

Republicans and Democrats jousted over alleged security failures, the administration’s fluctuating accounts of what happened, and the State Department rejection of U.S. Embassy requests to extend the tours of security personnel even as the danger of being in Libya grew.

“I believe, personally, with more assets, more resources, just meeting the minimum standards, we could have and should have saved the life of Ambassador Stevens and the other people who were there,” asserted Rep. Jason Chaffetz, R-Utah, who is helping lead the House Oversight and Government Reform Committee investigation into the attack.

Democrats retorted by pointing out that the Republican-controlled House of Representatives has been slashing proposed budgets for the State Department’s Bureau of Diplomatic Security, which protects 275 U.S. diplomatic missions, many of them in conflict zones.

Republican presidential contender Mitt Romney’s campaign weighed in after the hearing, accusing President Barack Obama of misleading the nation about what happened.

But it also said that Romney had agreed to stop telling the story of Glen Doherty, one of two former Navy SEALs who died, after his mother complained to a Boston TV station that it was “wrong” for the former Massachusetts governor to “make my son’s death part of his political agenda.”

At the White House, spokesman Jay Carney conceded that in hindsight “there is no question that the security was not enough to prevent that tragedy from happening.”

But Eric Allan Nordstrom, who served as the chief security officer at the U.S. Embassy in Tripoli from September 2011 until July, testified that the “ferocity and intensity” of the attack on the rented Benghazi compound that served as a temporary consulate exceeded any violence that he had seen in Libya or elsewhere.