Most people do not fully understand how an amendment can be proposed and ratified. As someone who teaches history and government, it's part of my job to understand this process. Article V of the Constitution lays out the processes by which constitutional amendments can be proposed and ratified. It begins with the proposing of the amendment which can be done in one of two ways.
In the first method which takes place in the U.S. Congress, both the House of Representatives and the Senate must approve the amendment by a two-thirds supermajority vote, a joint resolution amending the Constitution. Amendments so approved do not require the signature of the President of the United States and are sent directly to the states for ratification. The second method, which has never been used, requires two-thirds (or 34) of the state legislatures to ask Congress to call a national convention to propose amendments.
Of these two processes, it is unlikely that a new Equal Rights Amendment as I outlined on Monday could pass by a supermajority of both houses of the current Congress. The atmosphere is highly politicized with Republicans largely against equality for LGBT Americans and Democrats largely for LGBT equality. With Democrats not holding a supermajority in both house, it is highly unlikely to be able to move through Congress.
However, 34 states legislatures could call for a national convention. The likelihood of this is fairly slim because it's never been done before, and the majority of state legislatures, roughly 60 percent are controlled by Republicans. However, the majority of Americans, even if you go by state-by-state polls, favor same-sex marriage. At least, two-thirds of the states have 50 percent or more of its citizens who favor same-sex marriage. If the majority of citizens in favor of marriage equality in those 34 states became vocal enough, then state legislatures might be convinced to vote for a national convention for proposing amendments. This is also a tricky prospect because it would depend on who the states sent to a national convention and whether or not they would even even choose to propose a new ERA. The precedent set by the original Constitutional Convention would point to a national convention throwing out their mandate and proposing completely different amendments.
If a new ERA were proposed by a national convention, then it would move to the states for the ratification process. Again, Article V recognizes two ways for this to be accomplished. An amendment could be added to the Constitution if three-fourths of the state legislatures approve it. States may also choose to call ratifying conventions in which three-fourths of the states approve it. This method has been used only once, to ratify the 21st Amendment, repealing Prohibition.
The fact is, I realize this is a dream. Even with the 30 states that currently have same-sex marriage legalized, not all of those states would want to agree to a constitutional amendment for LGBT equality. Some polls show that in 38 states, there is a majority or near majority of people who believe that same-sex marriages should be recognized. The Pew Research poll which looked at regional support of same-sex marriage showed that only 34 states supported same-sex marriage, with basically the old Confederate states of the South, plus Kentucky, Oklahoma, and West Virginia being opposed to same-sex marriage.
Of the thousands of proposals that have been made to amend the Constitution, only 33 obtained the necessary two-thirds vote in Congress. Of those 33, only 27 amendments (including the Bill of Rights) have been ratified. It's a long shot but with enough momentum and support behind it, it is a possibility.