 -- The Senate overwhelmingly passed a bill to slap new sanctions on Russia and prevent the White House from making any changes without Congressional review today despite the reservations expressed by the Trump administration.

The enormous support from the Senate sets up a showdown between Congress and President Trump. The president expressed a desire to work with Russia throughout his campaign and tasked his secretary of state with improving relations between the two countries, but his policies have faced backlash as several people in Trump's inner circle remain under investigation by Congress and the Department of Justice in probes of Russian meddling in the 2016 election.

The bill mainly imposes new sanctions on Iran, targeting any individual or company that aids the country’s ballistic missile program, as well as Iran’s Revolutionary Guard Corps. After the Senate passed an amendment to the bill by 97 to 2, it now goes after Russia as well.

It hits Russia with new sanctions and codifies the existing ones imposed by the Obama administration for Russia’s occupation of Crimea and incursion into eastern Ukraine as well as its military intervention in Syria and its interference in the 2016 U.S. presidential election. The proposed legislation also mandates that the White House has to come to Congress if it wants to make any changes to sanctions.

The Trump administration reportedly wanted to lift sanctions on Russia when the president first came into office, according to former U.S. officials in government at the time. Alarmed by that prospect, a behind-the-scenes campaign began to prevent them from doing so.

While they ultimately decided not to lift sanctions, the administration has expressed reservations about the new bill. Although they have offered no official position yet, Secretary of State Rex Tillerson testified before Congress Tuesday and Wednesday, telling both chambers that he wanted “flexibility” to deal with the Russians himself.

Tillerson has said Trump tasked him with a “re-engagement process with Russia,” including greater cooperation in Syria and deputy-level meetings to deal with "irritants" in the relationship.

“I certainly agree with the sentiment that has been conveyed by several members from both parties that Russia must be held accountable for its meddling in U.S. elections,” he said before the House Foreign Affairs Committee Wednesday, but added, “We would ask for the flexibility to turn the heat up when we need to, but also to ensure that we have the ability to maintain a constructive dialogue.”

The bill strips the executive branch of that flexibility. But if the president vetoes the legislation -- after questioning whether Russia did meddle in the election and amid the ongoing investigations -- it could anger even Republicans and bring about an embarrassing override.

“If the president doesn’t sign this bill to punish Russia, he would be betraying democracy,” said Sen. Lindsey Graham (R-SC) on CBS’s “Face the Nation” Sunday.

Graham also introduced an amendment to the bill to reaffirm U.S. support for NATO and Article 5 of its charter, which promises common defense if any one NATO member is attacked. After bashing the alliance for months, Trump conspicuously left out any mention of Article 5 in a speech at NATO headquarters after senior administration officials said he would reaffirm America’s commitment to it.

The amendment passed 100-0.

Instead of giving any warning to the Trump administration, Senate Majority Leader Mitch McConnell (R-KY) cast blame on Obama and praised the bill’s bipartisan nature.

“After eight years of failed foreign policy under the Obama Administration — eight years of following the Obama Administration’s preferred strategy of drawing down both our forces and commitments — we must take a stronger stance in deterring Iran and holding its regime accountable for its actions and addressing Russia’s years-long pattern of provocations,” McConnell said on the Senate floor.

Russia has threatened to retaliate if Trump signs the legislation, but said they will await HIS reaction first.

“We need to wait for the final decision by the Congress, to see the reaction of U.S. President Donald Trump, but if the law is passed we will certainly not leave this move unanswered,” said Vladimir Dzhabarov, the first deputy chairman of the Russian parliament's international affairs committee, according to the Russian government-controlled news agency Sputnik.

The House will take up the legislation next, although it has not yet scheduled any vote.