Joe Biden ranas a unifying centrist destined to be in conflict with activist liberals. Turns out, Biden is governing as an activist liberal constrained by centrists. 

Why it matters: Biden has outlined the most liberal agenda in a generation. But centrist Democrats, including Sen. Joe Manchin (D-W.Va.), are potential deal-killers on climate change, spending and immigration reform.  

It's the Manchins of the world who could slow, if not stop, efforts to end the filibuster — the single biggest obstacle to enacting a truly liberal agenda.

• On top of Biden's expansive agenda, add Speaker Pelosi — a progressive who always wants to go big, and is thinking about her legacy — and Senate Majority Leader Chuck Schumer, who worries about a primary from his left.

Between the lines: The Biden team sees him as an activist president, but with an agenda that commands broad support.

• A FiveThirtyEight polling analysis finds majority support for 13 of 14 Biden executive actions in Week 1. (Canceling the Keystone pipeline got a plurality.)
• The country doesn't see it as liberal to fight the pandemic, racism or climate change.

What to watch: Centrist Democratic senators — including Manchin; Kyrsten Sinema and Mark Kelly, both of Arizona; and Michael Bennet of Colorado — hold high cards.

• With the Senate split 50-50, and Vice President Harris breaking ties, Biden needs every Democrat, even if the party uses budget reconciliation or ditches the filibuster rule — both mechanisms for passing bills with a simple majority.
• And Biden first will try to govern normally, which means 60 votes, and bringing some Republicans on board.
• Manchin complainedto WSAZ-TV in Huntington, W.Va., about an interview Harris had given the station to push Biden's $1.9 trillion COVID rescue plan: "I couldn’t believe it. No one called me. ... That’s not a way of working together."

Between the lines: Matt Bennett — a founder of Third Way, which champions center-left ideas — said the way to think about Biden's agenda is that he isn't "a '90s small government centrist and never has been. ... He wants to do big things, but only things that work."

• So Biden is pursuing "big ideas on climate, economic opportunity, child poverty, health care," but rejecting "far-left ideas like Medicare for All, the Green New Deal (including banning all fracking), abolish ICE, Defund the Police, universal basic income, etc."

The big picture: It might not happen fast. But many top Democrats believe Biden may eventually embrace eliminating the filibuster, so they can do bigger liberal projects that last much longer.