Senator Ben Cardin (D-MD) and Senator Tim Kaine (D-VA) gave Secretary of State nominee Rex Tillerson a tough grilling, asking critical questions about Tillerson's troubling ties to Russia and voicing concerns about the fossil fuel executive's views on climate change. And, on the Senate floor, Senator Chuck Schumer (D-NY) had strong words about Tillerson's loyalty to the nation.

In a continuing show of strength by Democrats in the confirmation hearings for President-elect Donald Trump’s cabinet nominees, Senator Ben Cardin (D-MD) today came out swinging against Rex Tillerson, the former CEO of ExxonMobil and Trump’s pick for Secretary of State.

Cardin has long hinted he would put up a fight over this nomination. In December, he released an official statement saying he was “deeply troubled” by Tillerson’s opposition to Russian sanctions.

In his opening statement, Cardin laid bare his skepticism that Tillerson’s experience in the fossil fuel industry suited him to be the top diplomat of the United States, saying, “Those who suggest that anyone who can run a successful business can of course run a government agency, do a profound disservice to both.”

Cardin, who had the first question, grilled Tillerson about Russia, specifically his beliefs on the Magnitsky Law. This law, first sponsored by Cardin himself in 2012, sanctions Russian officials who were responsible for the death in prison of a Russian lawyer who criticized the Kremlin.

CARDIN: Do you agree with me that creating stable democratic free societies around the world that support the aspirations of their people, including basic human rights, is in our long term national security interests?

TILLERSON: Without question, Senator.

CARDIN: And do you also agree that Russia, under Mr. Putin’s leadership, fails in that category?

TILLERSON: Yes, sir.

CARDIN: So, what we try to do, in order to provide national — international leadership, is to put a face on an issue. Thousands of people in Russia have been harmed or killed as a result of Mr. Putin’s leadership, and millions have been impacted by that. There is one person who lost his life in a courageous way — Sergei Magnitsky, a young attorney representing a client with U.S. interests, found corruption, did what any lawyer is supposed to do, reported it to the authorities. As a result, he was arrested, tortured, and killed. And those who benefited from the corruption were held with no accountability whatsoever. Through U.S. leadership, we’ve brought that case to the international forum. The Congress has passed a law, the Magnitsky Law. Other countries have now passed similar laws to deny our banking system and the right to visit our country to those who perpetrated those gross violations of human rights that were not held accountable by Russia. Do you support that law?

TILLERSON: Yes, sir, I do.

CARDIN: I thank you for that, because under the Obama administration, there have been 39 individuals who have been individually sanctioned under the Magnitsky Law, and five more were recently added on Monday. That law provides for Congress to be able to submit, through appropriate channels, additional names to be reviewed by the administration for inclusion for sanctions. Do you commit that you will follow that provision on names that we submit to you for potential sanctions for human rights violations under the Magnitsky Law?

TILLERSON: Senator, I will ensure that if confirmed, myself and the State Department does comply with that law.

Putting Tillerson’s views about U.S. policy towards Russia on the record is critically important, considering that Tillerson is a recipient of the Russian Order of Friendship, and because Tillerson’s company has deep financial ties to Russia which would benefit from a mutual repeal of these sanctions. And Tillerson’s assurance that he would enforce the sanctions was a sharp reversal, since he and ExxonMobil have a history of lobbying against them.

Tillerson also tried to deny that he had lobbied against the sanctions, which was seemingly rebuffed by the committee chairman, Sen. Bob Corker (R-TN):

Cardin later moved on to climate change, asking Tillerson whether he endorses the Paris Agreement. This is another crucial line of questioning, since Tillerson’s company has spent years funding pseudoscience opposing climate research despite the fact that their scientists may have been aware of their impact on the environment.

CARDIN: …do you agree that the United States should continue in international leadership on climate change issues with the international community?

TILLERSON: I think it’s important that the United States maintain its seat at the table on the conversations around how to address threats of climate change, which do require a global response. No one country is going to solve this along.

Although Tillerson responded that it was “important” that the U.S. remain involved in international climate talks, he skirted directly saying whether or not he believes the country should be a leader of those talks.

Sen. Tim Kaine (D-VA) also questioned Tillerson on issues related to climate change and ExxonMobil, leading to a line from Tillerson that invoked laughter in the room, despite its dismissiveness.

[Kaine] asked Mr. Tillerson to clarify what Exxon Mobil knew about climate change despite its public claims through the years.

“Senator, since I’m no longer with Exxon Mobil, I’m in no position to speak on their behalf,” Mr. Tillerson said.

Mr. Kaine reminded Mr. Tillerson that he was asking about Mr. Tillerson’s own experience, which included more than four decades at Exxon. “Do you lack the knowledge to answer my question, or do you refuse to answer my question?” Mr. Kaine asked.

“A little of both,” Mr. Tillerson said, to laughs.

And later, on the Senate floor, Minority Leader Chuck Schumer (D-NY) raised his own grave concerns:

Unfortunately, this morning’s cabinet hearing on Mr. Tillerson’s nomination for Secretary of State is a troubling sign of things to come.

In one breath he said that the invasion of Crimea is a violation of international law, and in the next, he declined to commit to maintaining the existing sanctions regime against Russia…saying he wants to get classified briefings first and then consult with the President-elect.

But I remind the country, as my friend the Republican Senator from Florida did, that these sanctions are the result of past crimes. You don’t need a classified briefing to know what Russia has done in the past. To duck the question, and refuse to commit to continuing these sanctions is tantamount to sweeping Russia’s flouting of international norms under the rug. It says, “go ahead, interfere in our elections again. Nothing will happen to you.” It says the same to China, and Iran, and any other country that might try to hack.

He has also not committed to new sanctions. Just yesterday, a bipartisan group of Senators, including the Senators from South Carolina, Maryland, Florida, California, and Nebraska, introduced tough new sanctions on Russia for their interference in our elections. I support this effort and I believe the Senate should act on it soon.

I am very concerned that, thus far, the President-elect, Mr. Tillerson and Sen. Sessions have not endorsed these tough new sanctions.

The Senator from Florida — not from my party — also pressed Mr. Tillerson on a series of war crimes committed by the Assad regime and the Russian military in Syria. These crimes have been reported in the press and detailed extensively by people on the ground and discussed at length by my friend the Republican Senator from Arizona, Senator McCain. But Mr. Tillerson won’t even sufficiently acknowledge these violations of human rights and war crimes.

And finally, Madam President, I am very concerned that despite the fact that we have registered lobbying disclosures from Exxon Mobile itself, documenting their involvement in lobbying against Iran Sanctions, Mr. Tillerson said this morning that Exxon did not lobby on sanctions to his knowledge.

This comes on top of recent reports that Exxon avoided Iran Sanctions by dealing with Iran and other state sponsors of terror through a European subsidiary.

This is very, very concerning. And it raises real questions as to whether the President-elect and his cabinet is prepared to stand up to Putin, stand up to Iran, and represent the interests of the American people and defend our democratic allies around the world.

Madam President, my friends on the other side of the aisle have nearly universally criticized this President – President Obama – for his policy on Syria and for not being tough enough on Vladimir Putin. Republicans have always called themselves the Party of Reagan. I don’t need to remind any of them of his famous speech in West Berlin.

Now, it seems, this fundamental tenet of Republican foreign policy, and indeed our national foreign policy for the past few decades, is eroding before our very eyes.

Now, it seems, the President-elect and his cabinet may never address the international security policy challenges posed by Russia and state sponsors of terrorism like Iran and Syria.

If Mr. Tillerson cannot even say that he will support the existing sanctions, what kind of Secretary of State will he be? I’m worried.

These powerful words from Schumer, alongside the tough questioning from Cardin, Kaine, and others, put a harsh spotlight on the financial conflicts and troubling views which could affect Tillerson’s policy approaches as Secretary of State. Thanks to these Democrats, Tillerson is being publicly held to account for this reality.

And while he, like Trump’s other nominees, will likely be confirmed by the Republican majority, the Democrats are doing a very effective job of publicly exposing Tillerson’s record — and inextricably tying it to President-elect Donald Trump.

(Alison R. Parker contributed to this article.)