NEW YORK (AP) — Presidential politics move fast. What we're watching heading into a new week on the 2020 campaign:

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Days to Iowa caucuses: 21

Days to general election: 295

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THE NARRATIVE

This week features the final debate before voting begins in Iowa, making Tuesday night the most important night of the 2020 primary season so far. It comes as the political world grapples with the fallout of the Trump administration's military clash with Iran, the looming Senate impeachment trial and deep uncertainty about the direction of the Democratic primary. At this point, any one of the four top-tier candidates — Joe Biden, Pete Buttigieg, Bernie Sanders or Elizabeth Warren — has a legitimate chance to win the Iowa caucus.

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THE BIG QUESTIONS

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THE FINAL THOUGHT

President Donald Trump is keeping his eye on the prize. As Democrats gather in Iowa, the Republican president will spend Tuesday night rallying supporters in what may be the nation's most important general election battleground: Wisconsin. He opens the year with no serious primary challenge and more than $100 million in his campaign account. As their primary fight intensifies, remember that the real work has barely begun for Democrats in 2020.

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