Senate Republicans continued to raise the issue of Biden administration’s Iran policy in nomination hearings of top officials, with sharp questioning of Colin Kahl on Thursady, President Joe Biden’s nominee as top Pentagon policy adviser.

Kahl, who served as national security adviser to then Vice-President Joe Biden in the Obama administration, faced many questions for his previous support for the 2015 Iran nuclear deal and his current position on the issue. The Biden Administration is trying to revive the agreement abandoned by former President Donald Trump, which would entail lifting sanctions Trump imposed. Republicans argue that the US should now throw away its leverage before serious concessions from Iran.

Kahl was also questioned for what republicans said was his public partisan pronouncements during Donald Trump’s presidency, exhibiting tweets Kahl send in the past.

“We know that there is a new administration and that we will have policy disagreements that we will all try to work through,” said the ranking Republican on the panel, Sen. Jim Inhofe of Oklahoma. “But how will you rectify the fact that many Americans, including those who work at the Department of Defense, know you only through your very partisan comments? How can we be confident that you will be a model of nonpartisan policy analysis — which is what the job requires — if you are confirmed?”

Some Republicans threatened they will vote against Kahl’s nomination, but Democrats have the majority in all committees, and it is not clear if any Democrat would defect to the Republican side to derail his confirmation.

One tweet mentioned, as an example of Kahl’s public partisan posturing said, “The GOP used to pride itself as a party that put values front and center in US foreign policy. Now—as they debase themselves at the alter of Trump—they are the party of ethnic cleansing.”

"How can you reassure this committee that your hyper-partisan advocacy would not drive Pentagon decisions?" asked the senator from Oklahoma. Inhofe added that if he sounded a little upset, it was because "frankly, I am."

During Thursday's hearing, Kahl defended his concerns about Trump's 2018 pullout from the Iran deal and the decision to pile pressure on Tehran, including round after round of economic sanctions. Kahl at the time worried it would encourage Iran to increase its provocations and accelerate its nuclear program.

"Both of those things have happened in the last three years. Iran is a lot closer to the fissile material required for a nuclear weapon than they were at the end of the Obama administration," Kahl said. "And we've seen more attacks."

Republican Senator Joni Ernst from Iowa said she would not support Kahl's nomination and that members of the US military "deserve someone that will take a serious outlook to policy."

Republican Sen. Tom Cotton of Arkansas and others read a number of Kahl's tweets that condemned Republicans and the Trump administration. Cotton said the “volatile” tweets would hurt his ability to work with Congress, adding “your judgement around war and peace are almost always wrong.”

Kahl apologized and said the last several years had been "pretty polarizing on social media."

"I'm sure there are times that I got swept up in that," he said.

Democratic Senator Tim Kaine said Kahl's hearing was being used by critics to re-litigate the 2015 agreement. But similar tough questions were asked of Wendy Sherman, nominee for Deputy Secretary of State on Wednesday. Sherman who was one of the architects of the nuclear agreement known as JCPOA, went out of her way to placate Republican concerns, refusing to endorse the agreement.

“I remain clear-eyed about the threat that Iran poses to our interests and those of our allies,” Sherman said. “I would note that 2021 is not 2015, when the deal was agreed, nor 2016, when it was implemented. The facts on the ground have changed, the geopolitics of the region have changed, and the way forward must similarly change.”

Reporting by Reuters, AP