CNN  — 

Democratic Sen. Joe Manchin of West Virginia is a key vote crucial to President Joe Biden’s agenda with Capitol Hill bitterly divided along partisan lines.

Manchin has long been in the spotlight in Washington as a pivotal swing vote unafraid to break with his party over high-profile issues. But the focus on the conservative West Virginia Democrat has intensified in the early days of the Biden administration with Democrats controlling the narrowest possible majority in the Senate, which means the votes of every lawmaker carry outsized weight.

Facing GOP opposition to key Democratic priorities, many Democrats have intensified calls for the elimination of the filibuster, which sets a 60-vote threshold for most legislation and can be wielded by Republicans to block liberal agenda items. But Manchin has been a thorn in the side for those who want to get rid of the procedural tool as he has continued to make clear he won’t vote for its elimination.

A Democrat in a red state

Manchin represents the deeply red state of West Virginia, where voters turned out strongly in support of former President Donald Trump in both the 2016 and 2020 presidential elections. The Democratic Party once held major sway in the state, but its standing has seriously eroded over the years. In 2017, the state’s governor Jim Justice announced at a rally with Trump that he was switching parties from Democrat to Republican.

But Manchin has maintained a base of support in the state and despite facing attacks from all sides, he has managed to keep winning reelection to the Senate, most recently in 2018. On Capitol Hill, he chairs the Senate Energy and Natural Resources Committee and is a member of the Senate Democratic leadership team.

Before coming to Washington, Manchin served as the governor of West Virginia and before that served as a state legislator.

Manchin’s relationship to Biden and critical role in the Senate

Manchin has said that he has an open line of communication with the White House and a good relationship with Biden and Vice President Kamala Harris.

Of Biden specifically, he told CNN in April, “Whenever he calls me, he calls and then we have a good conversation. We’ve had a good friendship and relationship for a long time. We understand each other.”

“Kamala and I have been friends,” Manchin told CNN at the time. “We sat together and had a great relationship … and still do. And the vice president and President is and always will be invited, no matter who they may be, to the state of West Virginia, and I’ll be there to meet them.”

Manchin told CNN in 2017 that his rapport with Trump was better than his relationship with former President Barack Obama, of which he said, “there was none.”

In an apparent sign of tensions within the party, however, Biden recently took a thinly veiled swipe at Manchin along with Arizona Democratic Sen. Kyrsten Sinema, though he did not reference them by name.

“I hear all the folks on TV saying, ‘why doesn’t Biden get this done? Oh, because Biden only has a majority of effectively four votes in the House and a tie in the Senate, with two members of the Senate who vote more with my Republican friends,” he said.

Manchin and Sinema actually vote more with Democrats than Republicans, but aren’t always aligned with the Democratic caucus on some of the key parts of Biden’s agenda. Both Democratic senators score 100% on a tracker from FiveThirtyEight of how often lawmakers vote in line with Biden’s position. Sinema, however, like Manchin, also opposes eliminating the filibuster.

Key votes and positions Manchin has taken

Manchin broke with Democrats in the midst of a highly contentious Supreme Court confirmation fight over Brett Kavanaugh to vote with Republicans in support of the nominee.

He also supported Trump’s first Supreme Court nominee, Neil Gorsuch, but he opposed what he described as the “rushed confirmation” of Amy Coney Barrett, Trump’s final nomination to the high court.

Manchin also stood with Democrats in opposition to President Trump and GOP efforts to repeal the Affordable Care Act and push through a Republican tax bill.

Manchin is not supporting a major voting overhaul bill that Democrats have made a top priority in Congress. The legislation faces unified Republican opposition and Manchin has argued that voting legislation should be enacted on a bipartisan basis.

Instead, Manchin and GOP Alaska Sen. Lisa Murkowski put out a letter last month urging Congress to find a bipartisan path forward to reauthorize the decades-old Voting Rights Act.

“Inaction is not an option,” they wrote. “Congress must come together – just as we have done time and again – to reaffirm our longstanding bipartisan commitment to free, accessible, and secure elections for all.”

CNN’s Ted Barrett and Ashley Killough contributed to this report.