At his confirmation hearing on Wednesday, President-elect Donald Trump’s secretary of state pick Rex Tillerson took harsh questioning from the Senate Foreign Relations Committee about his business dealings in Russia during his career as CEO of Exxon Mobil Corp.

In a moment where Russia is under fire for interfering in the U.S. election, and the Kremlin’s fingerprints are all over some of the world’s dominant conflicts, including the war in Syria and fight against ISIS, senators pressured Tillerson on whether he could respond appropriately given his private sector experience.

Sen. Marco Rubio, R-Fla., who ran for president against Trump, pressed Tillerson on whether he backs the assessment of U.S. intelligence agencies about Russia’s election-year hacking.

“Do you believe during the 2016 presidential campaign that Russian intelligence services directed a campaign of measures involving the hacking of emails, the strategic leak of emails, the use of internet trolls, and dissemination of fake news to denigrate a presidential candidate and undermine faith in our election process?” Rubio asked.

Tillerson described the findings by the intelligence agencies as “clearly troubling,” and called cyber attacks from foreign actors such as Russia “the greatest and most complex threat” facing the country today. He labeled Russia’s annexation of Crimea to be “illegal” and proposed tougher measures to combat the Kremlin’s invasion of eastern Ukraine, vowing that he would advocate providing Ukrainian soldiers with weapons.

But Tillerson expressed hope that he could help improve relations with Russia, potentially seeking to ally with it in areas of common interest even if America “will not likely to be ever friends with the Kremlin.”

“Dialogue is critical so these [issues] don’t spin out of control,” Tillerson said. “We need to move Russia from adversary always to partner at times.”

He was also unwilling to criticize Russia’s president, Vladimir Putin.

Pushed by Rubio on if Putin is a “war criminal” for actions taken by his military in Aleppo, Syria, Tillerson did not commit to that position.

“I would not use that term,” Tillerson said. “Those are very, very serious charges to make, and I want to have much more information.”

Rubio criticized Tillerson’s response as “discouraging.”

After a second heated exchange between the two later in the hearing, Tillerson sought to reassure Rubio.

“Our interests are not different senator,” he said. “There seems to be some misunderstanding. I share the same values as you.”

Here are nine more highlights from the hearing, in which Tillerson portrayed his views on America’s place in the world order as “indispensable in providing the stability to prevent another world war, increase global prosperity, and encourage the expansion of liberty.”

1. Fight Against ISIS

Tillerson considers the ongoing military campaign to defeat the Islamic State, or ISIS, the “most urgent” foreign policy challenge.

He is critical of the Obama administration’s approach to the Syrian conflict, where ISIS headquarters its self-declared caliphate, arguing that the U.S.’ cautiousness emboldened Russia to intervene in a much-criticized bid to boost the country’s dictator, President Bashar al-Assad.

Tillerson conceded that beating ISIS “won’t occur on the battlefield alone” and he vowed to win a “war of ideas” that he said requires a more “honest approach” to combating the ideology of radical Islam. He added that moderate Muslims are “our greatest allies in this war.”

The former Exxon Mobil chief advocated separating two major challenges in Syria—defeating ISIS, and influencing the country’s political future—rather than trying to tackle them at the same time.

“The clear priority is to defeat ISIS,” Tillerson said. “If we defeat ISIS, it will create some stability, and then you need to ask the question of what comes next and can we have influence over that or not.”

2. Sanctions

Tillerson declared sanctions to be a “powerful” tool of diplomacy, but he detailed a cautious, deliberative approach to how he would advocate using them.

Rubio pressed Tillerson about whether he would support economic sanctions on Russia or other countries in response to cyber attacks.

Tillerson replied that he would take a case-by-case approach, weighing other issues relating to the relevant country, including trade relations and other national security interests.

Confronting criticisms of his advocacy related to previous U.S. sanctions against Russia and how they impacted Exxon Mobil’s business dealings in the country, Tillerson claimed that he has “never lobbied against sanctions personally, and to my knowledge, Exxon has never directly lobbied against sanctions.”

He said that sanctions were an insufficient response to Ukraine’s taking of Crimea, and that there should have also been a “show of force—a military response in a defensive posture to send the message ‘it stops here.’”

He credited tough sanctions—supported by the U.S. and others in the international community—with bringing Iran to the negotiating table over its nuclear program.

3. Commitment to NATO

In the presidential campaign, Trump questioned the NATO alliance, and said members need to do more to earn the U.S.’ support.

Tillerson expressed a stronger commitment to NATO, promising to follow Article 5 of the treaty that enshrines the principle that an attack against one member is an attack against all.

“The Article 5 commitment is invaluable and the U.S. will stand by the commitment,” Tillerson said.

He also expressed concern for Baltic states that worry about Russian incursion on their borders.

“Our NATO allies are right to be alarmed about a resurgent Russia,” Tillerson said.

4. Trade

In another contrast with Trump, Tillerson did not say he explicitly opposes the Obama administration’s Trans-Pacific Partnership trade deal.

“I do not oppose TPP, but I share some of Trump’s concerns that it doesn’t fully support American interests,” Tillerson said.

But Tillerson seemed to support Trump’s campaign promise to renegotiate the North American Free Trade Agreement, a deal that went into force in 1994 under which the United States does not impose tariffs on products imported from Mexico and Canada.

More broadly, Tillerson said free trade between nations “is critical to the success of our foreign policy.”

5. Climate Change

Echoing Exxon Mobil’s evolving calculus on climate change, Tillerson said he recognized the threat of a warming planet, and that the U.S. should “be at the table” in coming up with solutions to limit greenhouse gas emissions.

If confirmed, he said he and others in the Trump administration would review the 180-country Paris climate change agreement before deciding whether to remain party to it.

“It’s important that the United States maintain its seat at the table with the conversations around how to deal with the threats of climate change,” he said.

As chief of Exxon Mobil, Tillerson publicly backed a tax on carbon in 2009, and expressed support for the Paris Agreement in 2015.

Yet, late in the hearing, he seemed to downplay the threat of climate change.

“I don’t see [climate change] as the imminent national security threat as perhaps other do,” Tillerson said.

6. China and North Korea

Tillerson referred to China’s island-building in the South China Sea as an “illegal” activity in disputed territory and “akin to Russia’s taking of Crimea.”

He criticized China for not fully enforcing U.N. sanctions against North Korea for its nuclear weapons program.

“If China is not going to comply with those U.N. sanctions, then it’s appropriate for the United States to consider actions to compel them to comply,” Tillerson said.

But like Russia, Tillerson said the U.S. should work with China where it can, on economic issues and in the fight against terrorism.

“We need to see the positive dimensions in our relationship with China as well,” Tillerson said. “The economic well-being of our two nations is deeply intertwined.”

Tillerson also said he would not advocate other countries expanding their nuclear capabilities, as Trump has suggested countries like South Korea and Japan should do.

“I don’t think anyone advocates for more nuclear weapons on the planet,” Tillerson said.

7. Israel

Tillerson said the U.S. will likely look to repair its relationship with Israel following the strained ties between the Obama administration and Prime Minister Benjamin Netanyahu.

He criticized the U.N.’s resolution condemning Israeli settlements in the West Bank and east Jerusalem, saying that the U.S. decision to not block the measure “undermines” potential future peace talks.

“We have to recommit our obligations to Israel as most important strategic partner in the region,” Tillerson said.

8. Mexico

Responding to concerns from Sen. Bob Menendez, D-N.J., that the Trump administration will “wall off” Mexico, Tillerson said the U.S. needs to engage with its southern neighbor.

He also refused to endorse Trump’s harsh rhetoric about Mexicans who immigrate illegally to the U.S.

“I would never characterize an entire population of people with any single label,” Tillerson said. “Mexico is a longstanding neighbor and friend with this country.”

9. Cuba

While arguing that the Cuban people “got almost nothing” in the Obama administration’s deal to open relations with the island, Tillerson would not say whether he would keep the renewed ties.

In a nod to Rubio, a Cuban-American who opposes the opening, Tillerson said he would veto legislation ending the U.S. embargo against Cuba if it were passed in Congress before the Trump administration reviews the Obama administration’s policy.