(CNN) With 50 days until the Iowa caucuses, the 2020 election will be here before you know it. Every Sunday, I outline the 5 BIG storylines you need to know to understand the upcoming week on the campaign trail. And they're ranked -- so the No. 1 story is the most important of the coming week.

5. Here comes Mike...: With his campaign's TV ad spending soaring above $100 million, former New York City Mayor Michael Bloomberg is starting to see some return on his investment.

A Fox News poll released Sunday put Bloomberg at 5% nationally, putting him behind only the presumed top tier of former Vice President Joe Biden (30%), Vermont Sen. Bernie Sanders (20%), Massachusetts Sen. Elizabeth Warren (13%) and South Bend, Indiana, mayor Pete Buttigieg (7%). (Bloomberg is tied with Minnesota Sen. Amy Klobuchar.)

Bloomberg's showing in the Fox poll matches where he was nationally in new Quinnipiac and Monmouth polls released over the past week. And while 5% isn't, well, 25%, it does suggest that the former mayor's massive ad spending is beginning to have an effect.

Remember, too, that Bloomberg is running a national strategy as opposed to an early state one. Bloomberg is effectively skipping all four votes in February (Iowa, New Hampshire, Nevada and South Carolina) in order to focus his time and money on Super Tuesday (March 3) and beyond, when the vast majority of Democratic delegates will be allocated. Given that approach, national polling may be more relevant right now to measure Bloomberg's growth and chances than early state data.

Even with Bloomberg's early gains, he still needs help to be viable come March. If a single candidate sweeps the first four states (or even wins three of the four), the race may be all but over when the calendar turns to March. The more chaos in February, then, the better for Bloomberg.

4. Trump goes to Michigan: President Donald Trump is scheduled to hold a President Donald Trump is scheduled to hold a "Merry Christmas" rally on Wednesday night in Battle Creek, Michigan -- which sets up a remarkable split-screen: The House voting to impeach Trump on one side and the President stumping for his reelection on the other.

The coincidence of timing could make for one of Trump's most memorable rallies. While he has sought to shrug off the impeachment charges publicly, CNN reporting makes clear that he is privately quite agitated about the whole thing. And if there's ever a time and a place where Trump will let what he thinks on the inside come out, it's in a campaign rally -- surrounded by thousands of cheering faithful -- in the middle of the impeachment proceedings.

The juxtaposition of the rally and the likely vote also speak to another reality: Trump's unique ability to counter-program the news. While attendees of the Michigan rally will, no doubt, be aware of the impeachment drama, they will take the news (and analysis) of the whole thing from Trump himself. Ditto for hardcore Trump supporters, who either see highlights of the speech or watch it themselves online.

3. A rebellion against the DNC: On the eve of this week's sixth debate in California -- more on that below! -- there's already a fight over the debates scheduled for the new year.

Nine candidates signed onto a letter to the Democratic National Committee over the weekend that demands that the committee lower its standards to qualify for the coming debates -- insisting they exclude candidates of color. (The effort is being led by New Jersey Sen. Cory Booker, who is set to miss his first debate of the race on Thursday.)

For its part, the DNC seemed unmoved. "The DNC will not change the threshold for any one candidate and will not revert back to two consecutive nights with more than a dozen candidates," said a spokeswoman for the committee.

At issue is the DNC's criteria, which, for this December debate included more than 200,000 unique donors and four polls in national or early states in which a candidate gets 4% support or more. (A candidate could also qualify with two national or early state polls that show him or her at 6% or higher.)

It seems unlikely the DNC will budge -- at least based on this single letter. The committee's stated goal was to ensure the debate process was fair, yes, but also that as the votes got closer the field was winnowed down to candidates able to demonstrate clear support.

If the DNC holds firm, it is likely curtains for the likes of Booker and former San Antonio Mayor Julián Castro who didn't make this week's debate and seem very unlikely to meet the rising DNC criteria.

2. The sixth debate is coming (or is it??): On Thursday, the seven top Democratic candidates will be at Loyola Marymount University for the sixth Democratic debate. It's the smallest number of candidates to qualify for any of the six debates and should provide a better opportunity for the top candidates to engage with one another -- and draw clear contrasts on critical issues most notably health care.

That's if the debate happens of course. Last Friday, all seven participating candidates said they would not cross the picket line of a labor dispute between a local food workers' union and Sodexo. The debate's location has already been moved once -- from UCLA after another labor dispute.

Assuming the debate happens -- and there's too much riding on it for it to not -- expect Buttigieg to come under the scrutiny that everyone expected him to face in the last debate just before Thanksgiving. (Buttigieg largely got a pass in that debate because the moderators seemed entirely uninterested in allowing the candidates to actually, you know, debate one another.)

A strong showing by Biden would cement his late momentum -- although the former vice president has struggled to put together a single solid debate yet. Warren needs to re-find her spark in the race after two less-than-impressive debate over the last two months. And it's getting late for Klobuchar to make her move.

1. The biggest week of the Trump presidency is here: Assuming all goes according to plan, the Democratic-controlled House will impeach Trump on two articles -- abuse of power and obstruction of Congress -- sometime on Wednesday. At which point the articles will be sent to the Senate for a trial that will begin shortly after Congress returns in the new year. No matter what happens in the Senate trial, Trump will be, after this week, only the third president to be impeached by the House.

While there's little doubt that Democrats will pass both articles of impeachment, the vote will still be a telling indicator of party unity -- and nerves.

Two Democrats -- Rep. Jeff Van Drew (New Jersey) and Collin Peterson (Minnesota) -- voted against the move to formalize the impeachment inquiry earlier this fall, and likely will vote against the articles, too. It's not clear whether Van Drew will do so as a Republican or a Democrat, however. He is expected to switch parties sometime in the very near future.

The question for Democrats is how many other members join that duo in opposing either one or both articles of impeachment. The key group to watch is the 31 Democrats (including Peterson and Van Drew) who represent seats that Trump won in 2016. So far, none of those Democrats have come out against either article of impeachment. But there's still 72 hours before the vote.

For Republicans, Trump is hoping to replicate the floor vote on formalizing the impeachment inquiry, when not a single GOPer voted "yes." And so far, no Republican has publicly announced plans to break ranks.

If Trump can hold all House Republicans in line, it makes it much, much easier for the President and his allies to make the case that this is a purely partisan and political endeavor by Democrats. And it would also send a clear message to on-the-fence Republican senators about which way the wind is blowing.

No matter what happens next, this week is history.