I had a conversation with a friend yesterday about marriage equality, and he noted how surprisingly quickly things were moving right now — three states last fall and three more this spring, with Illinois still a possibility over the next week — and wondered if I thought that meant we might see the freedom to marry recognized in half of the states within a year or two.

My answer was that while I’m certainly elated about the recent developments in Rhode Island, Delaware and Minnesota, I’m a little more cautious — one might even use the word “pessimistic,” modified by “mildly” — about predicting that we’ll see much more progress beyond them any time soon, because those states were, comparatively, the easy wins, the low-hanging fruit. Neither Rhode Island nor Delaware had laws specifically banning the freedom to marry and, in fact, both offered civil unions already; Minnesota did have a statutory ban, but a constitutional amendment was defeated there last fall.

But 30 other states have amended their constitutions to ban the freedom to marry — and some have gone even further, banning civil unions and domestic partnerships as well — and it is not a simple matter to repeal such amendments. Each state has a different process for doing so; in some, only the legislature can begin the process of amending the constitution, in others citizens may do so by ballot initiative. In nearly all cases, however, amending the constitution is neither an easy, quick, or inexpensive undertaking.

Nevada, for example, actually has begun the process to reverse the state’s constitutional ban on marriage equality. In Nevada, it takes about three years to do so; two successive legislatures have to pass the same language, and then it can go to the electorate in the following election. The current state legislature, which sits through 2014, has just taken the first step this week. Now we have to wait for the 2015 legislature to approve the same language, and the people finally would get to vote for it — in November, 2016.

Even in Nevada where the legislature and the electorate seem ready and willing to approve marriage equality, procedurally they cannot do so until three and a half years from now.

But what about those states where the legislature is more hostile to same-sex couples? In states where the amendment process must be initiated by the legislature, a single chamber under the control of anti-equality politicians could thwart the desire of the majority of the electorate and block even allowing the process to begin. We see this happening time and time again at the federal level already, where LGBT Americans are unable to get legislation prohibiting discrimination against them in employment, immigration or public accommodations, despite significant majorities of the American public supporting such legislation and opposing such discrimination, because of the dominance of anti-gay legislators in the House of Representatives.