WASHINGTON – A 2016 presidential longshot in each party contest – Donald Trump in the Republican and Bernie Sanders in the Democratic – is currently applying pressures on the other candidates, but in distinctly different ways.

Trump is swinging a sledgehammer on the GOP field with his racist assault on Mexican border-crossers by labeling them rapists and criminals. It is a totally irresponsible grab for public attention, with little regard to the party’s reputation and image.

Sanders is less bombastically reminding the Democratic Party of its historical New Deal principles as protector of the nation’s have-nots and middle class. He is focusing on the avarice of “the billionaire class” of corporate America, Wall Street bankers and investors, with a more aggressive pursuit of those principles.

Trump so far is an equal-opportunity wrecking machine, targeted against the whole Republican field, with the possible exception of Sen. Ted Cruz of Texas. Cruz has been defending Trump, obviously with an eye to vying with him for the anti-immigration crowd. Together they ignore and disdain the GOP’s need to cut into the Democratic dominance among Latino voters.

Sanders, in drawing uncommon large crowds this early in the election cycle, is challenging the perception of Hillary Clinton’s inevitability as the Democratic nominee. He is outdoing her in embracing the wide swath of unvarnished liberal positions on domestic and foreign policy issues.

His efforts may succeed in pulling the former first lady closer to the Democratic progressive base, thus enhancing her bid for the party’s nomination and her chances against an eventual Republican nominee badly wounded by its Trump-driven internal chaos.

Of the two forces being brought to bear on the parties, the Trump wrecking ball is clearly the more lethal. It not only spotlights the GOP’s problem with Latinos but also its general anti-government hostility, not to mention Trump’s personal baggage as a loose cannon.

The very fact that 16 Republicans have declared or are contemplating their candidacy for president, with no clear frontrunner in sight, invites the impression of disarray. The timid pleading with Trump to lower his decibel level by Republican National Chairman Reince Priebus is like, in the old Boston expression, trying to talk a dog off a meat wagon.

Sanders, on the other hand, is preaching time-honored social-democratic gospel, not surprising from a self-declared socialist, defending the little guy and working stiff against the avarice of corporate America. He is doing so as the Democratic Party is harping on income inequality – from a low and stagnant federal minimum wage to the huge disparity between lunch-bucket take-home pay and the billions going to Wall Street tycoons (and The Donald).

Hillary Clinton, of course, is working the same side of the street as a champion of the poor and middle class. But she does so from a perch of personal wealth based largely on offshoots of her and her husband’s public service.

Trump’s early showing in the polls reflects name recognition and a certain carnival allure that defies serious presidential aspirations. Sanders, as the longest-serving member of Congress, has credibility in his own right, though he remains a very long shot for the presidency.

An earlier fire-breathing liberal with socialist views, Chicago community organizer Saul Alinsky, endessly urged his disciples to “rub raw the sores of discontent.” The more courtly Sanders is putting a persuasive and less threatening face on the old class warfare.

In a way, Trump’s egotistical and wildly destructive presence in the Republican array of 2016 presidential wannabes can make the improbable Bernie Sanders of Vermont look highly responsible and worthy of being listened to on the Democratic side.

Also, the early crowd response to Sanders can remind Hillary Clinton that the strong liberal roots in the party that gave Barack Obama his 2008 victory over her remain a force she must continue to court. In doing so, it need not be in competition with Sanders, but rather in a shared fight against income and class inequality that seems increasingly in vogue.