To gauge how Democrats and Republicans perceive their relative strengths in Washington today, the State of the Union address by President Barack Obama and the response by Republican Senator Marco Rubio of Florida are useful guides.

Obama, who spent his first term hemmed in by constraints -- fiscal crisis, skittish Democrats and then, starting in 2011, a Republican majority determined to destroy his presidency -- is still operating in a box. Republicans have a majority in the House and an operational veto over the Senate, where they have made 60 votes the threshold for passing legislation.

Yet Obama staked out a series of distinct confrontations over specific policies that he supports and Republicans oppose. His liberal wish list included a rise in the minimum wage, universal pre-kindergarten education, gun regulation, immigration reform, restrictions on greenhouse gases and investment in infrastructure and green energy. The speech was a relentless assertion of liberal principles by a politician who, judging by a seemingly boundless confidence, appears to think the public has his back.

Rubio's response, in contrast, was almost entirely defensive. He complained about Obamacare (but offered no alternative, naturally) and dragged the old Romney-Ryan campaign straw men out of storage. Climate change? "Government can't control the weather." Safety net? "There are valid reasons to be concerned about the President's plan to grow our government."

As Josh Barro points out, three months after Republicans lost the White House along with seats in both houses of Congress, Rubio's remarks were devoid of the one quality Republicans need above all: newness. Rubio even cited his party's "detailed and credible plan that helps save Medicare." That would be the same plan that voters soundly rejected in public opinion polls in 2012, including the poll that really counted in November.

Rubio's defensive crouch was indicative of his party as a whole: Faced with undeniable proof that their policies are unpopular, Republicans are nevertheless terrified of change, fearful of alienating the conservative base voters whose anger they cultivated so assiduously just a short while ago. If Obama seemed especially jaunty delivering his remarks, he had reason. It's hard for Republicans to appear threatening to their opponents when they are cowering in fear of their friends.

(Francis Wilkinson is a member of the Bloomberg View editorial board. Follow him on Twitter.)