Enthusiasm for the Democratic Party is waning among young voters, so-called millennials, as its candidates head into the crucial midterm congressional elections, according to the Reuters/Ipsos national opinion poll. The online survey of more than 16,000 registered voters ages 18 to 34 shows their support for Democrats over Republicans for Congress slipped by about 9 percentage points over the past two years, to 46 percent overall. And they increasingly say the Republican Party is a better steward of the economy. Although nearly two of three young voters polled said they do not like Republican President Donald Trump, their distaste for...