Washington CNN  — 

With just 12 words, Nancy Pelosi changed everything.

“The President must be held accountable,” said Pelosi. “No one is above the law.”

That pronouncement came at the close of a press conference Tuesday afternoon, in which the Speaker announced that the House would open a formal impeachment inquiry into Donald Trump’s conduct as President.

At the most basic level, what Pelosi’s announcement means is that we will – at some point in the not-too-distant future – almost certainly have a full House vote on whether Trump deserves to be impeached. And with Democrats solidly in control in the House, Pelosi’s action on Tuesday means that Trump is now very likely to be the first president since Bill Clinton back in late 1998 to be impeached. (Clinton was acquitted by the Senate and remained in office. That, at least at the moment, seems the likely outcome for Trump too, because of the Republican majority in the Senate.)

Pelosi, of course, knew what she would be starting if she allowed a formal impeachment inquiry to go forward. The genie is out of the bottle now. The wheels have begun turning and churning to the near-inevitable outcome: A President impeached by the House.

What is less clear is what an impeached – but (likely) not removed – Trump means for our politics. There are some near-certain impacts like a hardening of the already deeply polarized party bases, for one. And Trump claiming himself as the victim of a massive Democratic witch hunt for another. (Again, Pelosi knew this; she was wary of allowing Trump to play the role of victim he loves so much.)

But how does all of this land with a public that generally speaking views Trump dimly, but also has to this point opposed impeaching him? Does this simply affirm their view that politics is broken and that a pox is deservedly cast on both party houses? Do they eventually conclude that Democrats overreached, fueled by their hatred of Trump? Or maybe they decide that Trump’s conduct in office – and particularly his conversation with the Ukrainian president about unproven allegations regarding Joe Biden – is so beyond the pale that impeachment, as opposed to the 2020 election, is the only recourse for the country?

What’s abundantly clear is that this impeachment fight – both during the investigation and after the near-inevitable House vote and Senate trial – will blot out the sun in Washington. Gun legislation now takes a backseat. Immigration, too. Everything but must-pass legislation will be affected.

The media coverage coming out of Congress – and Washington more generally – will be all about impeachment. The 2020 Democratic campaign will be dominated by it.

Trump’s presidency – and the way in which the two political parties react to it – has been fundamentally altered by Pelosi’s announcement on Tuesday. This is as big as it gets in politics: Massive stakes with neither side certain of how it all ends, but absolutely sure that whatever happens will have consequences that extend long beyond this year – or even Trump’s presidency.

The Point: The train has left the station. It’s buckle-up time.