The Note: Primary Primer

— -- NOTABLES

--5 STORYLINES TO WATCH TONIGHT: Republicans will vote today in the Idaho, Michigan and Mississippi primaries and the Hawaii Republican caucuses. Democrats in Michigan and Mississippi are also holding their primaries. In total, 205 delegates are at stake for the two Democratic candidates. On the other side of the aisle, 150 are up for grabs for the four remaining Republican candidates. ABC’s PAOLA CHAVEZ and VERONICA STRACQUALURSI note what each to look for on Tuesday as voters in four states cast their ballots. http://abcn.ws/1Tnfzzd

--ANALYSIS -- ABC’s RICK KLEIN: A divided Republican Party means Donald Trump conquers. Unless the party isn’t divided enough for a contested convention… The latest ABC News/Washington Post poll finds Trump behind both Ted Cruz and Marco Rubio in two-way races – races, of course, that may never come. The calendar is such that it might offer just enough encouragement to all the would-be Trump rivals to soldier on, beyond the point even when any of them can hope to win more delegates than the others. The exception may be Cruz, who faces a critical test in Tuesday’s contests. A second-place finish in Michigan can seal his role as the main Trump alternative. A win elsewhere – Idaho? a much more valuable Mississippi? – would mean he is consistently beating Trump, a claim no one else can make. The bottom line is that Trump is vulnerable. The rest of the GOP, though, is caught between cohesion and division – agreeing on the stop-Trump goal, disagreeing on the tactics – to an extent that those vulnerabilities still might not matter.

--FOR RUBIO, IS IT TOO LATE TO BE THE UNDERDOG? While teaching at Florida International University in 2011, Marco Rubio told his students there were two ways a candidate could be successful: He or she had to be a self-funder or the candidate needed to be “a sensation, a symbol larger than themselves.” In his Senate race, Rubio was, indeed, a sensation -- the underdog in the race against Charlie Crist, then the sitting governor of Florida. This time around, Rubio hoped for a repeat of that. But as he struggles to generate enthusiasm for his campaign (Rubio has lost 18 of the first 20 primary contests), it appears the dynamics of 2016 aren’t on his side. So what's going on? ABC’s INES DE LA CUETARA has more. http://abcn.ws/1Sv5b7H

TRUMP ON ‘GMA’ CALLS COMPARISONS TO ADOLF HITLER 'TERRIBLE'. Republican presidential front-runner Donald Trump says that he thinks comparing the tone of his campaign to that of Adolf Hitler is "terrible." "It’s a terrible comparison," he told ABC’s GEORGE STEPHANOPOULOS on "Good Morning America" today, adding that he hadn't heard of the comparison yet. "I’m not happy about that certainly. I don't want that comparison." Mexican president Peña Nieto likened Trump's campaign tone on Monday to those of Adolf Hitler and Benito Mussolini during their rises to power. Comedian Louis C.K. and conservative journalist Glenn Beck have also compared the real estate mogul to Hitler in recent days. When asked whether these comparisons meant that he should tone down his rhetoric, Trump said "maybe so," but added that he continues to see strong support in recent polling and at the ballot box. ABC’s RYAN STRUYK has more: http://abcn.ws/1RxZIYP

BY THE NUMBERS: TRUMP HITS A WALL WITHIN THE GOP. Donald Trump’s facing a wall within his party, with Republicans who don’t currently support him far more apt to prefer Ted Cruz or Marco Rubio in a two-way race -- or even to favor a contested convention to block Trump’s nomination. Trump continues to lead in a new ABC News/Washington Post poll, with 34 percent of Republicans and Republican-leaning Independents who are registered to vote saying they’d like to see him win the nomination, according to ABC’s GARY LANGER. http://abcn.ws/1YoRA20

--BUT HE TRAILS BOTH CRUZ AND RUBIO ONE-ON-ONE: And preferences for Cruz, Rubio and John Kasich have grown as others have left the race, while Trump’s support has essentially remained unchanged for months. In the current multi-candidate race, 25 percent say they’d like to see Cruz win the nomination, with 18 percent for Rubio and 13 percent for Kasich; those are +4, +7 and +11 points compared with January, respectively, to new highs for each. Trump, by contrast, peaked at 38 percent in December. (In a difference from previous matchups, this poll asked respondents whom they’d like to see win, rather than whom they’d vote for, since the primaries are underway.) http://abcn.ws/1YoRA20

YESTERDAY ON THE TRAIL with ABC’s VERONICA STRACQUALURSI and PAOLA CHAVEZ

CLINTON PLEDGES TO NEVER LET DONALD TRUMP BECOME PRESIDENT. Hillary Clinton took direct aim at Donald Trump during a rally in Detroit last night, vowing to never let the Republican front-runner become president as she continued to shift her focus away from Bernie Sanders and toward the GOP field, ABC’s LIZ KREUTZ reports. “Because of the kind of campaign that the Republicans have been running, led by their front-runner, we have a lot of people who have been attacked, right?” Clinton asked the crowd of roughly 850 people at the Charles H. Wright Museum of African American History in Detroit. http://abcn.ws/1SvQNMo

SANDERS ACCUSES HILLARY CLINTON OF ‘CATEGORICALLY UNTRUE’ STATEMENTS ON HIS RECORD. Bernie Sanders fired back at Hillary Clinton Monday, telling crowds and reporters during a whirlwind day of campaigning in Michigan that what Clinton said about his voting record with regards to the automobile industry bailout was “categorically untrue.” “Secretary Clinton tried to make the point that I did not support the bailout of the automobile industry and the millions of jobs that were at stake,” Sanders said, referring to comments Clinton made during last night’s CNN debate. “The only problem with her assertion is that it is categorically untrue.” ABC’s MARYALICE PARKS has more. http://abcn.ws/1SvAD5D

WHY THE REAL CONTESTED GOP CONVENTION BATTLE COULD START IN APRIL. Imagine a floor fight with chaotic eleventh-hour negotiating at the July Republican convention in Cleveland. It’s possible – but the real battle would quietly be beginning months before that. More than half of the Republican presidential delegates awarded from primaries and caucuses will be allocated after March 15, but the selection of individuals serving as delegates to the Republican convention will just be getting started, a new ABC News analysis shows. Even though roughly six in 10 of the Republican delegates will be allotted after Ohio and Florida vote in mid-March, a mere 21 percent of the individual delegates filling those roles will be chosen at that point in time. ABC’s RYAN STRUYK has more. http://abcn.ws/1SvfRTG

IN CASE YOU MISSED IT

BLOOMBERG WON’T RUN. Billionaire businessman and former New York Mayor Michael Bloomberg wrote in an op-ed Monday that he will not be running in the 2016 presidential election. In the op-ed, Bloomberg writes that being a 2016 presidential candidate is “not a risk” he could take “in good conscience." “As the race stands now, with Republicans in charge of both Houses, there is a good chance that my candidacy could lead to the election of Donald Trump or Senator Ted Cruz,” Bloomberg wrote. “That is not a risk I can take in good conscience.” According to ABC’s VERONICA STRACQUALURSI and RYAN STRUYK, Bloomberg also used his op-ed to attack Donald Trump, arguing the Republican front-runner "appeals to our worst impulses" and he is running the "most divisive and demagogic presidential campaign I can remember." http://abcn.ws/1p3bXp6

WHO’S TWEETING?

@DLeonhardt: How to know if Trump is slipping: Does he hit ~35% in Michigan and ~42% in Mississippi tonight? http://www.nytimes.com/2016/03/09/us/politics/primary-elections-preview.html …

@BenjySarlin: This week will go a long way to deciding if Trump's the nominee: http://www.msnbc.com/msnbc/the-week-could-determine-the-gop-nominee …

@gdebenedetti: .@jameshohmann is right: Clinton's made a point to zero in on hyper-local issues *early* in each state she's visited http://wapo.st/1U1szKW 

@TomBevanRCP: .@BrucePurple on RCP: Two Trends, One Trigger. The 25 Year Tide That Gave Us Trump http://www.realclearpolitics.com/articles/2016/03/08/the_25-year_tide_that_gave_us_trump_129902.html …

@CapehartJ: Is it me or does Claire Underwood seem EXTRA cold this season? @HouseofCards