Clinton's remarks were a note of caution in an otherwise fairly triumphant three-day gathering.
Democrats note that Republicans have given way on taxes, long their guiding star. The GOP reluctantly went along with a proposal to conclude the "fiscal cliff" drama which allowed income taxes to increase on couples making more than $450,000 a year.
An immigration overhaul, once thought virtually impossible in the face of an implacable Republican House majority, now seems like a clear possibility.
And after the Newtown, Conn., school massacre, a long-dormant discussion of gun control has dominated the national news for weeks.
"To the degree that the Democratic caucus is included and some of our views are addressed in legislation, it's good for the nation," said Rep. Ed Perlmutter, D-Colo.
The other reason for House Democrats' high spirits? An understanding that the Republican majority needs them. House Speaker John Boehner, R-Ohio, has time and again relied on the votes of Democrats to help move must-pass legislation when a bloc of 50 or more of his own conservative members has refused to go along.
Without Democrats, the fiscal-cliff bill would not have been adopted. Nor would a bill to provide billions in aid to victims of Hurricane Sandy that had threatened to become a massive public-relations problem for the national Republican Party. When Democrats refused to go along with Boehner's proposed solution to the fiscal cliff in December — which would have allowed taxes to increase only on income over $1 million a year — the plan collapsed in an embarrassing failure because of Boehner's inability to get a majority of 218 votes from his own members.
Even a measure adopted last month to suspend the nation's debt ceiling for three months — an idea advanced by Republican leaders and which enjoyed broad support within the party — still drew 33 Republican "no" votes and would have fallen short without Democratic support.