1. Pulling her to the left Bernie Sanders speaks at the Iowa Democratic Party's Hall of Fame dinner. Credit:Reuters Clinton has already taken various positions on economic and social issues that are clearly a reaction to the Sanders' threat from the far left. In recent months, Clinton's political and rhetorical message has boiled down to an Old-Democrat, big-government, Pelosi-Reid-AFL-CIO-pleasing stew that a skillful Republican nominee could exploit, shoving Clinton out of the vital political middle in the general election. 2. Exposing her biggest weaknesses Even some of Clinton's staunchest backers will tell you she comes off to many voters as personally inauthentic and politically calculating, lacking a genuine, heartfelt message. Even some of Sanders' biggest detractors will tell you he is exactly the opposite. Sanders has become such a prodigious performer on the stump and in TV interviews in part because he gives Democrats an unvarnished and passionate view of his ideas, his soul, and himself. Recently, at a major gathering of Iowa Democratic activists, almost every Clinton supporter to whom I talked expressed admiration for Sanders' authenticity and policy agenda, and many said that if they followed their heart, they would vote for the underdog. If Clinton's main four-point agenda sounds like the product of extensive research by her polling and focus-group teams, well, that is because it is. A lot of voters grasp that calculation intuitively, and find it a turnoff. Clinton's perceived lack of personal and political sincerity might not cost her the nomination, but it won't help her image with general-election voters already sceptical about her character and relatability.

3. Forcing her to go negative Democratic presidential candidate and US senator Bernie Sanders speaks at a rally in Dallas. Credit:Reuters When front-runners are threatened, their usual move is to kneecap the opponent and, before too long, Clinton might feel she has no choice but attack Sanders. Such a move might be effective, but it would hold peril. First, as Sanders himself has eschewed negative politics throughout his career, potent political martyrdom could ensue. Second, Clinton could look like a hypocrite, since she has been regularly railing against negative attacks from the GOP. Third, it could unleash even more vigorous Republican assaults, with far less concern about public or media backlash. 4. Playing a losing expectations game Clinton faces a daunting expectations game. Even if she heads into Iowa and New Hampshire with solid polling leads, simply winning will not be enough. She has to finish far enough ahead of Sanders to prevent the media from treating a win like a loss. Between now and early February, polls will rise and fall, and what will constitute a win for Clinton will change. But rest assured, the media will give her zero benefit of the doubt in this regard. Even if Clinton wins Iowa, say, 66 per cent to 33 per cent in an historic landslide, some news organisations would likely headline their stories "One third of Iowa Democrats reject Clinton". Clinton will thus have to spend a great deal of time and money in the two early states (which demographically and ideologically are among Sanders' strongest), leaving her vulnerable in some of the later-voting states and hindering the timely formulation of a general-election strategy or message.

5. Beating her in early states If Sanders continues to build his momentum and cut into Clinton's lead, and she becomes sidetracked by controversy (typically a given, when a Clinton is on the ballot), it is not inconceivable Sanders could win one or both of the two first states. That would instantly throw the party into a second-guessing panic. Panic, needless to say, would not help Clinton look like a general-election juggernaut. 6. Forcing her to invest more in caucus states As a hedge against early losses, and with the memory of being outfoxed by Team Obama in 2008, Clinton's campaign is going to pour resources into the post-Iowa caucus states, where Sanders' grassroots enthusiasm allows him to compete fiercely. Caucuses and primaries are state-level elections to determine which candidates receive party support going into the national conventions. Once again, this dynamic means Clinton has to continue to take left-wing positions and to devote precious resources to targeting small numbers of activists, rather than building a general-election machine. 7. Forcing her into an extended nomination fight

If Sanders has early success, the media and the left (not to mention the GOP) will be eager to see how far he can go. That will mean the Clinton campaign will have to continue to allocate resources away from a general-election fight. The longer Sanders stays alive, the greater the aforementioned party panic would be. Bill Clinton dealt with this dynamic in 1992, when, amid scandal, he struggled to put away Paul Tsongas and Jerry Brown. As the conventional wisdom refrain declares, Hillary Clinton does not have her husband's political skills – it would be more difficult for her to quash a widespread party freakout. And it wasn't easy for Bill Clinton. Now, of course, these are mostly speculative scenarios. But none is impossible or even improbable. All derive directly from Sanders' manifest strengths, Clinton's manifest weaknesses, and the dynamics and realities of the Democratic Party's nomination process. Not long ago, few would have imagined Sanders could have posed any sort of threat to Clinton's political fortunes. Sanders might lose in the end, but his successes thus far and going forward make it more likely Clinton will lose in the end, too. Bloomberg Follow FairfaxForeign on Twitter Follow FairfaxForeign on Facebook