Both sides, in good faith

The strongest fair case each way — we don't pick a winner.

The case for

Supporters of the renaming would argue that a nation has the sovereign right to name geographic features within its own jurisdiction as it sees fit, and that adopting a unifying name such as “Lake America” can be seen as an assertion of national pride and identity, particularly at a time of economic and trade tension with a neighbouring country. They may also point out that the change applies only to how the United States refers to the lake for its own purposes, leaving Canada and international map-makers free to continue using “Lake Ontario”, so the practical impact on cross-border relations or historical record-keeping is limited.

The case against

Opponents, including many residents on both sides of the border, would argue that the name “Lake Ontario” carries deep historical and cultural significance, rooted in an Indigenous Wendat-derived word, and reflects centuries of shared heritage between local communities and Canada. They would contend that unilaterally renaming a shared natural landmark disregards this history and the identity of the towns and people connected to it, and risks needlessly inflaming an already strained relationship with a close ally and trading partner over a symbolic gesture with little practical benefit.