Veto power gets a bad reputation in polyamory circles, and not without reason. The idea that one partner can unilaterally end another's relationship sits uncomfortably alongside the core CNM principle that everyone's needs and autonomy matter. But the veto persists, couples keep including it in their agreements, often early on when they're navigating new territory, and understanding why reveals something useful about what it actually is and what it isn't.
What a veto is
A veto, in CNM terms, is an agreement that one partner has the power to end or significantly restrict another partner's outside relationship, typically without requiring justification that meets any particular standard. "I'm not comfortable with this" is, by definition, sufficient. The partner subject to the veto agrees to honour it.
Vetoes are more common in early CNM arrangements, particularly when one partner initiated the open relationship and the other is more reluctant or uncertain. They function as a safety net: if this gets too uncomfortable, there's an exit mechanism that restores the original equilibrium.
The case for having one
The honest version of the argument for veto power is this: opening a relationship involves taking on real risk. A veto represents a mutual agreement that the original partnership comes first, that if the new structure produces serious distress, the partnership has a formal mechanism for addressing it.
For some couples, especially those early in the process, this functions as a scaffold. Knowing the veto exists reduces anxiety enough to actually try non-monogamy rather than abandoning it preemptively. The safety net isn't expected to be used, it's expected to make the attempt possible.
There's also a coordination argument: in relationships where one partner opens reluctantly, a veto may be the price of genuine consent rather than reluctant acquiescence. A partner who consents to an open relationship in part because they have a veto may be consenting more genuinely than one who consents without it but resents the arrangement in practice.
The case against
The standard critique goes: veto power treats third parties as expendable. The person who might be vetoed out of a relationship has invested emotional energy, time, and genuine care, and the veto can end that regardless of how well the relationship is going, for reasons that might have nothing to do with anything they've done. They have no voice in the decision and no recourse.
There's a power asymmetry embedded in the structure. The person with the veto has security; the outside partner has uncertainty. The veto doesn't protect both people equally, it protects the existing partnership at the cost of everyone else's investment.
There's also a practical problem: vetoes don't actually solve the underlying issue. If one partner vetoes an outside relationship because they feel neglected, the neglect doesn't end with the relationship, it just re-emerges. If the veto is triggered by jealousy rather than a genuine threat, exercising it provides temporary relief without addressing what the jealousy was about. Vetoes can become a tool for managing discomfort rather than engaging with it.
How vetoes tend to work in practice
When vetoes work as intended, rarely invoked, functioning primarily as psychological safety, they often fade out of the agreement naturally. As partners become more experienced with CNM, more confident in the relationship, and more skilled at handling difficult emotions, the veto stops feeling necessary. Many couples who started with veto agreements remove them after a year or two without it feeling like a significant concession.
When vetoes work poorly, they get deployed as a management tool, triggered not by genuine distress about the outside relationship but by jealousy, insecurity, or scheduling conflicts that could be resolved other ways. Someone who has used a veto multiple times, in response to partners who weren't doing anything wrong, has probably converted it from a safety net into a control mechanism, whether or not they recognise it.
The warning sign isn't the existence of a veto, it's frequency of use and the pattern of what triggers it. If you're considering entering a relationship where a veto exists, the relevant question isn't "do they have a veto?" It's "has it been used, under what circumstances, and what happened to the person on the receiving end?"
Alternatives that accomplish more
Most of what vetoes are meant to accomplish can be achieved through other mechanisms that don't carry the same costs.
Check-ins and slow pacing. If the concern is that things are moving faster than one partner is comfortable with, an agreement to check in regularly, with explicit permission to say "I need us to slow down", addresses the underlying issue without the nuclear option.
Agreed exclusions. If there are specific categories of connection that feel genuinely off-limits, workplace relationships, situations involving specific levels of entanglement, those can be negotiated as agreements rather than veto triggers. This is more honest about what the concern actually is.
The real conversation. In most cases, a veto impulse is a symptom of something, unmet needs, inadequate time together, fears that aren't being addressed. The veto prevents having that conversation by providing a shortcut. Having the conversation is harder and more uncomfortable and more useful.
What actually matters
The veto debate in CNM communities sometimes gets treated as a values question, are you the kind of person who believes in autonomy or aren't you? That framing isn't particularly useful.
The more useful question is what the veto is actually doing in a specific relationship. Is it a genuine safety mechanism that reduces anxiety and enables participation? Or is it a control tool being used to manage an existing partner's discomfort at the expense of third parties?
If it's the former, it may serve a legitimate function for a period of time. If it's the latter, it's addressing the wrong problem, and the people most harmed by it are the ones least able to do anything about it.