PORTLAND, Ore. -- President Donald Trump’s Supreme Court nominee could have a more difficult path to the bench because of Senate rules that give Democrats the ability to require a supermajority for confirmation.

Trump nominated Judge Neil Gorsuch on Tuesday evening for the Supreme Court seat vacated when Justice Antonin Scalia died last February. Gorsuch currently is a federal judge on the U.S. Court of Appeals for the Tenth Circuit based in Colorado.

Gorsuch already appears likely to face roadblocks from Oregon’s two senators who will both vote on his confirmation.

Sen. Ron Wyden said he has “serious concerns” about Gorsuch, while Sen. Jeff Merkley said he will “do everything my power to stand up against this assault on the court.”

“The Gorsuch nomination represents a breathtaking retreat from the notion that Americans have a fundamental right to Constitutional liberties, and harkens back to the days when politicians restricted a people’s rights on a whim,” Wyden said in a statement.

Merkley on Tuesday evening reiterated his earlier promise block the nomination. He voted to invoke a rule requiring 60 votes in the Senate for a Supreme Court nominee to move forward.

“The most fundamental thing that must be understood about tonight’s announcement is that this is a stolen seat,” Merkley said. “This is the first time in American history that one party has blockaded a nominee for almost a year in order to deliver a seat to a President of their own party. If this tactic is rewarded rather than resisted, it will set a dangerous new precedent in American governance.”

Merkley and other Senate Democrats have more power to stall a Supreme Court confirmation compared to other presidential appointments. Senate rules give any senator the power to unilaterally require a 60-vote supermajority on Supreme Court nominees, whereas other appointees only require a simple majority.

A 2013 Senate rule change pushed by Democrats lowered the threshold for confirming members of the president’s cabinet and other executive branch appointees.

Republicans control 52 seats in the Senate. That’s enough to push through cabinet nominees without Democratic support, but not enough for a supermajority.

Wyden has already called into question Gorsuch’s thoughts on physician-assisted suicide, which is legal in Oregon.

Gorsuch wrote a book about the ethics of physician-assisted suicide called “The Future of Assisted Suicide and Euthanasia.” According to the publisher, the book makes the case against physician-assisted suicide on the grounds that “human life is intrinsically valuable and that intentional killing is always wrong.”

“His opposition to legal death with dignity as successfully practiced in Oregon is couched in the sort of jurisprudence that justified the horrific oppression of one group after another in our first two centuries,” Wyden said. “No senator who believes that individual rights are reserved to the people, and not the government, can support this nomination.”

In Washington state, Democratic senators Patty Murray and Maria Cantwell both said they had issues with Gorsuch's nomination.

"I have concerns about Judge Gorsuch's record on a number of important issues. We need a justice who will help move our country forward, not backwards, as part of a Court that recognizes settled law," Cantwell said.

"With so much chaos in the Administration and so many questions surrounding this President's commitment to the rule of law and the separation of powers--I have serious concerns about moving forward with a Supreme Court nomination at this time and will be joining those pushing back against jamming this nominee through or rushing a confirmation in any way," Murray said.

Gorsuch was previously confirmed by the Senate in 2006 for his position on the federal appeals court. The confirmation was done by “voice vote” where the names of senators voting on either side are not recorded. There was no opposition raised against Gorsuch at the time. Wyden, Murray and Cantwell were all in the Senate at the time.

Wyden said at the time Gorsuch didn’t have a judicial record to cause concern. But since then, Wyden argues his record is more concerning.

He specifically pointed to Gorusch’s arguments against physician-assisted suicide, which Oregon voters have approved.

“In his nomination hearing before the Judiciary Committee ten years ago, he claimed that he was able and willing to separate his own opinions from his judicial ones. However, in cases like Hobby Lobby since then, he has shown that his personal beliefs have, in fact, influenced his judicial decisions,” Wyden said.

A spokesman for Senate Majority Leader Sen. Mitch McConnell called Merkley a hypocrite for vowing to block Trump’s nominee.

"When Democrats were in the majority, Sen. Merkley wanted to end filibusters. But I guess he only meant when Democrats are in the majority and in control of the White House," McConnell’s spokesman Don Stewart told Politico on Monday.

A Merkley aide fired back, accusing McConnell of being the real hypocrite.

“Senator McConnell’s unprecedented and totally partisan blockade of Merrick Garland’s nomination, in which he refused to even allow hearings and votes, represents the ultimate assault on the democratic principles Senator Merkley has been fighting for,” said Merkley spokeswoman Martina McLennan. “Senator Merkley believes it would set a dangerous precedent to allow that assault to go unanswered. Indeed, it’s McConnell who is being hypocritical in insisting on a normal vetting process for this stolen seat after he pointedly refused to extend that same courtesy to the legitimate and mainstream nominee named by President Obama a year ago.”