Nevada vs Marriage

The Nevada legislature overrode the governor's veto last Sunday and signed into law domestic partnership rights. Linda McClain notes a peculiar aspect of the bill:

Nevada’s new law is available both to same-sex and opposite-sex couples…In this respect, Nevada is like several European countries where registered partnerships are available to opposite sex and same-sex couples. The Act does not include findings about why Nevada made this striking choice. Like others, I have argued that creating a new civil status alternative to civil marriage might provide a good option for heterosexual couples who resist marriage either because of its historical association with sex inequality or its religious connotations. Will any opposite-sex couples in Nevada choose this new status? Will critics charge that the Act weakens marriage precisely because it provides this alternative?
It almost certainly does weaken marriage; and it is not the exact equivalent of civil marriage either. It was precisely to avoid this predicament that many of us proposed simple marriage rights back in the 1980s.