Washington (CNN) Here are the stories our panel of top political reporters have on their radar, in this week's "Inside Politics" forecast.

1. Which states get hurt by Obamacare repeal?

Obamacare opponents won a key court victory last week that could lead to the eventual unraveling of the health care law.says Republicans might want to be careful what they wish for.

"Who's most at risk of being hurt if the entire thing is thrown out?" Talev asked. "Michigan, Pennsylvania, Ohio, New Hampshire -- big swing states -- are really in great jeopardy, and their rates could go up by 100% or more. ... So there could be a cost if the Republicans get their way."

2. 2020 Dems split on USMCA

President Donald Trump's new North American trade treaty, the USMCA , looks likely to be officially ratified after congressional Democrats negotiated some labor-friendly changes to the deal.

The House approved it last week, and the Senate is likely to do so next month -- but expect opposition from some of the Democrats' biggest names.

"A fascinating thing to watch will be the dividing lines among Democrats, particularly Senate Democrats, and particularly those running for the 2020 Democratic nomination," Washington Post reporter Seung Min Kim said.

"We saw a little bit of that at the debate on Thursday, when you saw Sen. Bernie Sanders saying he would not support the agreement ... that he's still concerned about outsourcing jobs to Mexico," Kim said. "But then you also saw Sen. Amy Klobuchar saying she'll support it, it's good for farmers. ... So it's going to be an interesting political question for Democrats. Do you get on board with this major Trump administration accomplishment, or go against something that's supported by a wide array of Democrats and very powerful unions?"

3. Warren's New Year's Eve reset

Meanwhile, New Year's Eve will mark the one-year anniversary of Sen. Elizabeth Warren jumping into the presidential race. She'll celebrate with a major campaign speech in Boston.

"Obviously impeachment has distracted so much from the campaign," CNN's Maeve Reston said. "So she's hoping to redefine the race at that moment, painting herself as the anti-corruption crusader against Trump, and trying to get a little bit of a lift from that third place she's in right now in the polls."

4. A rare sign of civility

After Trump attacked her late husband at a rally last week -- even implying that the long-time congressman was in hell -- Rep. Debbie Dingell (D-Michigan) found support on both sides of the aisle when she returned to Capitol Hill.

"We saw something striking happen the next morning on the House floor," Washington Post reporter Rachael Bade said. "Republicans who knew John Dingell, and are friends with Debbie Dingell, went up to her on the floor and were very apologetic for the President, hugging her, embracing her, including Louie Gohmert, who is one of President Trump's number one attack dogs in the House, apologizing for the President. It's a reminder that even though this partisan rancor has hit a fever pitch in Washington amid all the impeachment, there is some decency, still, in the halls of Congress."

5. Brace for 2020

And from CNN Chief National Correspondent John King:

The closing weeks of 2020 were packed with big political news -- from the impeachment debate and major spending agreements to a bipartisan deal to support the new United States-Mexico-Canada trade agreement.

It was a challenging stretch, but those leaving Washington and politics behind for a holiday break are mindful the early weeks of 2020 will be even more dizzying.

Consider just some of the entries on an early 2020 political calendar packed with consequence:

- The Senate impeachment trial sometime in January.

- A Democratic presidential debate.

- The State of the Union Address, likely on Feb 4.

- And the first four presidential nominating contests are sprinkled throughout February -- Iowa, New Hampshire, Nevada and South Carolina.

Busy, right? Yes, but those first two months are just the beginning.

March will truly roar in like a lion, and have a defining role in the 2020 presidential race.

The February contests are critical for momentum, especially with this crowded Democratic field and the added dynamic of former New York City Mayor Michael Bloomberg sitting the first four out but promising to make his move in March. But it is worth remembering those first contests combined award less than 5% of the total delegates to the Democratic nominating convention.

March is different.

Fourteen states, plus American Samoa, vote on March 3, with delegate-rich California and Texas the biggest Super Tuesday prizes.

Six more states choose the following Tuesday, March 10, with Michigan the biggest delegate prize that night.

Then four more a week later on St. Patrick's Day. Florida, Arizona, Illinois and Ohio hold primaries on March 17.

By the end of the month, some 70% of the Democratic delegates will be allocated. Is there a clear leader at that point? Or will there be a mix of February and March winners that leads to no one candidate building a clear and convincing delegate lead?

Former Clinton White House counselor and veteran Democratic strategist Doug Sosnik is among those who see March 17 as a 2020 crossroads moment. In a year-end memo looking at the 2020 environment, Sosnik puts it this way: "We will know if Democrats are on the path of selecting a nominee, or headed to an open convention for the first time since 1952."