Democrats are increasingly fearful that they are squandering a chance to flip a Senate seat in Ohio — a state that once seemed out of reach but, according to polls, remains competitive just four weeks before Election Day. Their main concern is that even though Democratic nominee Tim Ryan has raised significantly more funds than his Republican opponent, J.D. Vance, GOP-aligned groups have poured more than $30 million worth of advertising into Vance’s campaign, far outpacing the amount national Democratic groups have spent on Ryan.