In some battleground states, authorities have pursued charges against officials who have interfered in past votes

• US politics live – latest updates

Some US states are sending strong signals to county and local officials who might be tempted to intervene illegally in the 5 November election or refuse to certify results: fail to do your duty and risk criminal charges or hefty financial penalties.

In at least five of the seven battleground states that could determine whether the next US president is Democrat Kamala Harris or Republican Donald Trump, top election and law enforcement officials have investigated, indicted and even jailed officials who tried to interfere with the vote or delay certification of results, a necessary but largely ceremonial step.

Don’t miss important US election coverage. Get our free app and sign up for election alerts