Will challenger Mitt Romney win a first term as President, because he provides a similar alternative?
No. If Romney wins it will be because voters have lost faith in Obama on the economy. It might be like 1980 or 1992 or 1976 or 1932.
But even if the election will be about "left wing cultural chaos," the relevant comparison would not be to 1972, but to 1968, when the challenger scraped in because of social issues, rather than to the landslide reelection of an incumbent.
IMO, the 1968 election was about the several “long hot summers” of riots in the big cities - Watts, 1965, Detroit and Newark 1967, Harlem, 1964 - etc. Nixon was the ‘law and order’ president.