<p>A recovery, it appears, has begun. A potent jolt of monetary and fiscal stimulus is lifting consumer spending, and business confidence is reviving.</p>
<p>But the real challenge stretches into the next year: When the adrenaline rush of lower interest rates and big tax cuts ebbs, will the expansion have gained enough momentum to continue? Or will it fade, as earlier, stimulus-stoked expansions did in 2002 and again earlier this year?</p>