With a month to go until midterm elections, Democrats find themselves in better shape than expected. Odds are, they’ll win the House and perhaps a slim majority in the Senate. Exactly what they’ll do with that power, though, remains a mystery. On the campaign trail, most of the party’s congressional candidates have been long on rhetoric and short on policy. In lieu of an agenda, many are promising partisan warfare: more investigations of the president, expansive impeachment proceedings, subpoenas for documents and witnesses, aggressive oversight hearings, and more. All of which is fine as far as it goes. But the party must remember that voters have many worries on their minds, that the president’s cooperation will still be needed to pass bills — and that the country is facing real challenges that need real solutions. For starters, a lot of must-pass legislation is coming down the pike that will require cross-party cooperation, including a surface-transportation bill, a farm bill, a debt-ceiling extension, a defense reauthorization and the 12 standard appropriations bills neede