MITT ROMNEY, moderate. That earnestly sought post-debate public image contrasts starkly with Mr. Romney’s actual positions on many issues, especially the future trajectory of government spending.

Clinging tightly to a studied vagueness when pressed for unpopular specifics, Mr. Romney has put forward a budget framework that would not eviscerate Medicare and Social Security, as is commonly believed, but would slash everything else that’s not defense.

President Obama should use Tuesday night’s debate to press Mr. Romney to defend — or even just explain — these proposed cuts, which would be far more draconian than those advanced by his running mate, Paul D. Ryan. Mr. Ryan is widely viewed as the real fiscal hawk, but in key areas, his views on spending levels are actually closer to Mr. Obama’s than to Mr. Romney’s.

All in all, Mr. Ryan and Mr. Romney do see the future similarly — over the next decade, they want government spending reduced to about 20 percent of the United States’ gross domestic product, below the historic average of around 21 percent. (Recognizing that an aging society costs more, Mr. Obama proposes to hold spending at its current level, 23 percent.)