Though they don’t yet have a candidate for the Senate, Delaware Democrats are beginning to train their fire on Republican Rep. Michael N. Castle, who has the early edge in the race to succeed retiring Democratic Sen. Ted Kaufman.

The Democratic National Committee on Friday organized a conference call that was intended to pressure Castle into supporting a Democratic-written plan to overhaul health care policies. That bill, which is backed by the Obama administration, will receive a full House vote on Saturday.

“I think Delaware has made it clear that we want and need it,” said John Daniello, the chairman of the Delaware Democratic Party. “I hope, really, that Representative Castle chooses to stand and vote with the people he represents, not with his party leadership.”