By Nicole Gaouette

CNN

WASHINGTON (CNN) -- Rex Tillerson faces a grilling Wednesday at his Senate confirmation hearing to be secretary of state that comes after CNN reported that Russia may have compromising information about President-elect Donald Trump.

The former ExxonMobil CEO claims close ties to Russian President Vladimir Putin, having overseen the company's partnership with a state-owned energy giant there, work that earned him the country's highest award for non-citizens.

Questions about Tillerson's and Trump's ties to Moscow are expected to be front and center at the Senate Foreign Relations Committee hearing, but Republicans and Democrats alike will also question the nominee about his positions on Iran, sanctions, climate change and other issues as they vet him to be the top US diplomat.

In excerpts of his opening remarks released Tuesday night, Tillerson, in a sharp departure from Trump, adopts a tougher line on Moscow.

"Russia must know that we will be accountable to our commitments and those of our allies," Tillerson is set to say, adding that "Russia must be held to account for its actions."

The nominee is also expected to validate NATO allies' concerns about Russian aggression but say that some of the blame lies with the Obama administration. And he's due to strike a note of wary realism.

"We must also be clear-eyed about our relationship with Russia," Tillerson is expected to tell senators. "Russia today poses a danger, but it is not unpredictable in advancing its own interests."

The dark-horse candidate has already prompted concerns from human rights groups that cite his former company's practices and lawmakers who charge that he has a track record of putting profits before US interests, with one saying he could be a "disaster" as secretary of state.

Democrats will drill the 64-year-old on whether his business experience -- he's never served in government -- adequately prepares him for heading the State Department. Lawmakers on both sides will look to see whether Tillerson will balance out foreign policy positions that Trump has taken and that many on Capitol Hill see as extreme.

And at a time of deepening global upheaval, both Republicans and Democrats will seek to understand how Tillerson sees the world.

"He's somewhat a blank canvas," said Derek Chollet, an executive vice president at the German Marshall Fund.

"He's someone who's very experienced in the world, who has a lot of experience dealing with tricky issues with foreign counterparts. He's even probably pretty knowledgeable on issues like human rights because of the roles those issues play in the extractive industries," Chollet added. "But we don't know much about how he thinks. There's very little for anyone to draw on for specifics."

Tillerson's big moment in the spotlight comes as CNN reported Tuesday that US intelligence agencies are investigating reports that Russia collected sensitive and potentially compromising information about Trump's personal and financial affairs.

The information, from a firm run by a former British intelligence operative, also indicated that throughout the campaign, Trump surrogates were in touch with intermediaries for the Russian government. Sen. John McCain, an Arizona Republican, became aware of the information in December and passed it to FBI Director James Comey that month.

Republicans will be key to Tillerson's ability to get through the Foreign Relations Committee and to the Senate floor, where his nomination needs 51 votes to pass. The committee is controlled by Republicans, who hold 10 of the 19 seats. If all Democrats oppose him and they're joined by just one Republican, Tillerson could stall there.

Tillerson's emergence as a candidate for the post

The oil man, who had headed the ExxonMobil empire since 2006 until retiring at the end of last year, began his journey to Washington in Texas. He was born and educated there, and spent his adult life inside the company, starting in 1975 as a production engineer after graduating from the University of Texas at Austin. He's never worked anywhere else.

Tillerson emerged as a candidate for secretary of state after high-profile national security Republicans -- all of whom had worked for the oil company at some point -- recommended him to Trump. Former Secretaries of State Condoleezza Rice and James Baker, former National Security Adviser Stephen Hadley and former Defense Secretary Robert Gates sang Tillerson's praises.

He eventually won out over more well-known figures, including former Republican presidential candidate Mitt Romney and ex-UN Ambassador John Bolton. After Tillerson's nomination was announced, Washington watchers began sifting through his company's record for clues as to how he might perform on the world stage.

One Senate aide said Democrats are interested to see whether Tillerson could try to sway Trump to more moderate positions, who has raised the possibility of banning Muslims from entering the US, reviving torture practices like waterboarding and seeking warmer ties with Russia.

Tillerson built his career on exploration with Russian energy giant Rosneft, making Russia ExxonMobil's largest exploration theater. Russian officials hailed the announcement of Tillerson's nomination.

"Trump continues to amaze," said the head of the foreign affairs committee in the Russian parliament's lower house, Alexey Pushkov, who added that Tillerson would be a "sensation."

Trump has hinted at lifting sanctions on Russia, said Angela Stent, director of the Center for Eurasian, Russian and East European studies at Georgetown University, a step that could benefit ExxonMobil enormously.

"Out of all the energy companies, Exxon would be the biggest beneficiary," Brian Youngberg, a senior energy analyst at Edward Jones told CNN last month.

Tillerson has since moved to divest himself of his stock and of future payouts he was set to receive from the energy company. He has also said he would recuse himself from decisions that might affect the company for the first year of his tenure as secretary of state.

Democrats raise Tillerson ties to Russia

Sen. Robert Menendez, a New Jersey Democrat and foreign policy veteran, said that after meeting one-on-one with Tillerson he had "serious concerns about his world view and his overall depth of understanding of US foreign policy." He flagged the Texas millionaire's Russia views in particular.

Sen. Chris Murphy, a Connecticut Democrat on the committee who has already indicated he'll oppose Tillerson, said in December that the nominee "has spent his entire career putting oil company profits first and the interests of his country second."

He noted that Tillerson opposed sanctioning Russia for its invasion of Ukraine and annexation of Crimea and sent a deputy to a Russian economic conference during the Ukraine crisis after President Barack Obama asked US firms not to attend. At that conference, Exxon announced major new contracts with Russia.

Handing Tillerson "the keys of US foreign policy is a recipe for disaster," Murphy said.

ExxonMobil's dealings with Iran are also a red flag to some lawmakers on the committee.

Can the secretary of state nominee explain Trump?

As lawmakers push to have Tillerson outline his views on other nations, they'll also be asking him to explain the President-elect's positions.

Beyond the questions on Russia, they'll want to know what his plans are for managing the often-tense US relationship with China, how to handle the growing nuclear threat from North Korea, what to do about ISIS and the war in Syria, and his views on climate change and the Iran nuclear deal.

Unlike a typical presidential campaign, the Trump camp didn't issue many position papers outlining its policies and the candidate himself "didn't leave behind a body of foreign policy speeches that we can look back to," Chollet said.

Trump spokesman Sean Spicer has told reporters that Tillerson "will impress the hell out of" senators. "He is going to knock their socks off." He said that Tillerson would implement Trump's agenda once he's confirmed.

But privately, lawmakers and Senate aides say that Tillerson seems to have a more traditional world view than Trump, who has talked about dismantling security structures in place since World War II, including pushing Asian allies to develop nuclear weapons and questioning the value of NATO.

Tillerson sounds much more like "a standard conservative Republican in terms of his world view, which would seem diametrically opposed to the comments President-elect Trump has made on the campaign trail and has continued to make," said a Senate aide.

"We'll want to know how will he square these views with the foreign policy he'll be asked to carry out for President Trump."

Tillerson would be carrying out foreign policy at a time when the world seems to have become more uncertain, with China pushing aggressively against US power in Asia, the Mideast in flames, Europe destabilized by refugees fleeing the war in Syria and struggling with an increased terror threat from groups like ISIS.

The global uncertainty that Tillerson might have to wrestle with also stems, in part, from Trump's victory, Chollet said, adding that Trump's questioning of long-standing US alliances in Europe and Asia has unsettled allies.

The question they're asking themselves, Chollet said, is "if the US isn't going to be the bulwark of the global security order since WWII, it is going to be a disruptor of that order."