Speaker of the House Nancy Pelosi (D-CA) has given a stark warning to Democratic presidential contenders regarding major healthcare and tax proposals that are being promoted by some of the candidates, suggesting that it can hurt the party’s chances of defeating Donald Trump in the upcoming 2020 U.S Presidential Election.The pointed comments to her fellow Democrats were seen as targeting primary front runners Elizabeth Warren and Bernie Sanders, whom have been promoting programs such as Medicare For All and a wealth tax in recent debates, as well as within their platforms. Pelosi remarked that “what works in San Francisco does not necessarily work in Michigan,” while discussing the Democratic Primary at a round table of Bloomberg News reporters and editors on Friday. She further added that “what works in Michigan works in San Francisco — talking about workers’ rights and sharing prosperity.”Recent polls have indicated a tightening of the race between the three main front runners, Elizabeth Warren, Bernie Sanders and former Vice President Joe Biden, at the national level. An NBC News/Wall St. Journal poll gave Biden 27%, with Warren trailing at 23%, followed by Sanders with 19%.For the all-important Iowa Caucus set for February 3rd, 2020, which can serve as a springboard for establishing momentum in the race, the polls are even closer. A RealClear Politics aggregate poll from November 1st gave Elizabeth Warren 22.3%, followed by Pete Buttigieg (17%), Joe Biden (15.7%), Bernie Sanders (15.3%) and Amy Klobuchar (3.7%). The number of undecided voters still remains high, sitting at 13.2%.Pelosi’s remarks come amid increasing polarization within the Democratic Party between those seen as part of the moderate Democratic Party establishment, represented by Joe Biden and Pete Buttigieg, and those on its left-wing flank, Elizabeth Warren and self-declared democratic socialist Bernie Sanders.Warren responded to the criticism by attacking Joe Biden, suggesting that he is “running in the wrong presidential primary.” On the other hand, Warren has come under increasing scrutiny regarding some of her tax reform proposals due to her inability to demonstrate that her plan will not increase taxes on middle-class Americans.This is not the first time Pelosi, a liberal democrat, has come into conflict with other, more left-leaning Democratic politicians. Pelosi has spent much of the last year also in conflict with the “squad”, a set of four Democratic Congresswomen known for their progressive policy proposals on tax reform and climate change.