DANVILLE, Ky. — Vice President Joe Biden and Rep. Paul Ryan of Wisconsin tangled fiercely and noisily here Thursday night over the economy and foreign policy in a spirited debate that underscored the vast differences between the Democratic and Republican tickets on virtually every issue in the presidential campaign.

In sharp contrast to last week's exchange between President Barack Obama and Republican challenger Mitt Romney, the vice-presidential candidates clashed repeatedly during their 90-minute encounter. They differed over how to create jobs, who should and should not have their taxes cut or increased, how best to ensure the solvency of Medicare and Social Security, and whether the Obama administration's foreign policy in the Middle East and Afghanistan is working.

The other contrast with the first presidential debate was the absence of a clear winner. Romney was universally judged to have bested Obama in Denver, but Biden and Ryan each made their points with force and conviction. With the race tighter than it was two weeks ago, Thursday's debate is not likely to result in a significant shift toward either Obama or Romney but is likely to raise the stakes when the two meet next week for their second forum.