(Reuters) - Ricardo Aguirre sits near his two taco trucks and laments the soaring cost of tomatoes, onions, meat and cilantro, which have doubled in price in recent months, hammering his Phoenix-based catering business. Aguirre, 43, usually votes for the Democratic Party. But with inflation hitting a 40-year high in February he has a stark warning for Democrats as they seek to keep control of the U.S. Congress in November's elections. "If the Republican Party has something better to offer us, I will vote Republican," said Aguirre. Republicans, he believes, are generally better economic stewards who could have more success...