Increasing the production of alternative fuel in New York and other states should be a key component of America’s strategy for dealing with Iran, U.S. Senate candidate Kathleen Troia “KT” McFarland told The New York Sun.

In an interview on Wednesday, Ms. McFarland, who is locked in a nasty Republican primary battle against the former mayor of Yonkers, John Spencer, said increasing the domestic development of alternative fuels like ethanol, particularly in upstate New York, would help trigger a homegrown revolution in Iran and bring down the government in Tehran, which she described as the “biggest threat to world peace.”

The frustration of Iran’s youthful population, which she said is the country’s “Achilles heel,” would bubble over if America reduced its reliance on energy supplies from the Middle East. Oil prices would plummet, she said, and would force the Iranian government to scale back the “petrodollar”-funded subsidies that she said are keeping the population in check.

Ms. McFarland, 55, an Upper East resident whose last public sector job was serving as a speechwriter and spokeswoman under Defense Secretary Caspar Weinberger more than 20 years ago, said she would have voted for the war in Iraq, as her Democratic opponent Senator Clinton did in 2003, but said Congress failed to question the need for greater American troop levels to carry out the mission.

She supported the war, she said, because “you had to shake up, somehow, what was now becoming a series of monarchal sclerotic dictatorships that were now multigenerational. It made a lot of sense to stir the pot.”

The pot-stirring, however, ought to be limited to the Middle East, she said, saying China’s simmering dispute with Taiwan over the issue of Taiwanese independence is an “internal Chinese matter.”

On the issue of immigration, she said she opposed a mass expulsion of illegal immigrants or giving them a blanket amnesty. She said the borders first must be sealed with the use of buffer zones, high-tech surveillance, and drones. The next step would be for the government to expel those illegal immigrants who are convicted criminals. “Those people you do want to send back,” she said.

Ms. McFarland’s campaign has been seeking to distinguish itself from Mr. Spencer’s campaign by highlighting the candidate’s knowledge of foreign policy and casting Mr. Spencer, aVietnam veteran who started his career as a steamfitter, as a local politician who is out of his depth in world affairs. Both candidates are struggling to stay financially afloat and trail badly in the polls to Mrs. Clinton.

Overshadowing her campaign, however, has been a flood of press reports about her troubled family background centering on an accusation she made that her father abused her when she was a child. Her father has denied the claim.

She has sought to turn the tables by focusing attention on Mr. Spencer’s extramarital relationship with a former Yonkers City Hall staff member, Kathy Spring, whose salary almost tripled while she worked for him and who bore two of his children while he was still married. Mr. Spencer, who subsequently divorced his wife and married Mrs. Spring, insists that she was qualified for the job.

Ms. McFarland, who drew some criticism in political circles for dwelling on the affair during the candidates’ debate last week, said she had no regrets about her personal line of attack, saying Mr. Spencer “should be ashamed” of the way he conducted himself in office.

She said she would endorse him if he won the Republican primary on September 12 and would not run on an independent line.