This strategy has risks, as Nixon, who lost the presidency once and won it once by narrow margins, understood. Your right- or left-wing stances in the primaries can hurt in the general.
As happened to George McGovern, the leftward-tacking Democratic nominee in 1972, whom Nixon beat with 61 percent of the vote. In the four decades since only Ronald Reagan in 1984 came close to that percentage.
Hillary Clinton, whose husband ran McGovern's fall campaign in Texas (he won 33 percent there), seems to be taking the same risk. Presumably she does so with open eyes, aware that it might hurt her if nominated, but is more apprehensive about the primary fight than she was seven months ago, before the revelations about her private email server.
On immigration, for example, she promises to go at least one step further than President Obama. She endorses that his orders effectively legalize not only "dreamers" -- persons brought into the country illegally as children and who meet certain conditions -- but their parents.
That latter order has been put on hold by a federal judge. But that doesn't faze Clinton. "I will not be deporting parents. I will not be breaking up families," she told a Telemundo interviewer earlier this month.
For illegals, Clinton said a "path to citizenship" is "absolutely essential" -- a stand that contrasts even with such immigration-friendly Republicans as Jeb Bush, who advocates legalization but not citizenship for illegals.
And even more than Obama, she would use administrative powers to do what Congress declines to authorize. "I want to do more on an individual basis by putting more resources, more personnel into the system to try to help as many people as possible get a different status."
These stands are obviously designed to appeal to Hispanic primary voters. But while polls show that non-enforcement against dreamers is popular, administratively legalizing illegals may be a liability in any fall campaign.
Clinton is also willing to use administrative methods to restrict gun ownership. In New Hampshire this month she promised "executive action" of an unspecified nature to restrict gun sales. She also called for repeal of the 2005 law granting legal immunity from lawsuits for gun manufacturers and dealers.
That was obviously with an eye to primary voters, since her chief rival at the moment, Vermont Sen. Bernie Sanders, voted for that law. Vermont is one state that has never restricted gun ownership, and Sanders has voted against many, though not all, gun control measures -- a no-no for many Democratic primary voters.
So just as Mitt Romney went after Rick Perry four years ago on immigration -- one issue on which he was to the right of his then most threatening rival -- Hillary Clinton is going after Sanders on this one issue on which she stands to his left.
But this isn't ideal positioning, to say the least, for the general election. Al Gore is said to believe that Bill Clinton's championing of gun control cost Gore the electoral voters of their two home states -- and thus the 2000 election. Hillary Clinton's emphasis on gun control eliminates any chance she can carry such states and restricts her to the strategy of trying to re-assemble Barack Obama's 51 percent 2012 coalition.
Candidate Clinton, if nominated, is at risk of being associated with Obama's recent favorable evocation of Australia's gun confiscation law. Her stand on immigration gets her closer to the stance Bill Clinton took, in a speech in Australia on September 10, 2001, for eventual elimination of all national borders for trade and immigration.
Other cave-ins to the Democratic left -- her opposition to the Keystone XL pipeline, to Arctic oil drilling, to the Trans-Pacific Trade Partnership -- could hurt as well. Similarly, attempts to skitter away from her somewhat hawkish foreign policy views could be a general election liability.
Of course Republicans could have problems, too, with an unruly field and various candidates tacking to the right. But Clinton's risk is obvious.
She is not likely to match Obama's margins among black voters and may not match his Hispanic percentage. Add in losses from tacking too far left on immigration and guns, and she could fall below Nixon's two near-ties and sink toward McGovern's showing.