Your idea is right...but not the example
Muskie lost because Nixon supporters had hippies invade a Muskie fundraiser...freaking out big donor Dems...and closing their checkbooks for Muskie
Nixon and his advisors felt Muskie was the Dems best chance vs Nixon...and targeted him to upend his campaign
I remember the footage of Muskie defending his wife from the `evil rightwing’ Manchester Union Leader; snow was falling so he bowed his head to avoid the snowflakes getting into his eyes. The Nixon campaign exploited this as flakiness on Muskie’s part (pun semi-unintended).
McGovern won the nomination & his far flakier liberal & even pacifistic record guaranteed his defeat in ‘72.