Vice President Joe Biden, a man with nearly four decades of experience in politics, has not been taking lightly his preparations for his debate against Rep. Paul Ryan, R-Wis., holding practice sessions and perusing briefing books in recent months.

Now, in the wake of President Barack Obama’s widely panned performance last week in his first debate against Mitt Romney, the stakes for Biden are suddenly higher than ever.

In the Oct. 11 vice-presidential debate he must not only avoid making any gaffes but also try to puncture his Republican opponent’s arguments on taxes, entitlement reform and deficit reduction, something Obama was criticized for failing to do last week.

The pressure on Ryan has risen as well. Romney greatly exceeded expectations, appearing both presidential and in command of the debate stage. Ryan, who has never before debated at the national level, must prove that he is potential presidential material — while also defending the numbers that Romney put forth last week, especially on tax cuts.

Both sides are offering sky-high predictions for the other team. “There’s a lot on the line,” said Rep. Jason Chaffetz, R-Utah, a chief Romney-Ryan ally. “President Obama failed to defend his record and could not articulate a vision for the future. So I think that challenge now falls to Vice President Biden.”

Bill Burton, former White House deputy press secretary and co-founder of the Democratic super PAC Priorities USA, argued that the burden is actually on Ryan.

“Ryan is going to face pressure to explain some of the dishonest claims he and Romney have been making, especially on things like Medicare, taxes and the auto industry,” he said.

One point on which both sides appear to agree is that Biden is likely to be more aggressive in his faceoff against Ryan than Obama was debating Romney.

Both White House contenders have been deeply engaged in debate preparations even as they maintain busy schedules on the campaign trail.

For Biden, that has meant squeezing in time for debate preparations while visiting with his family in Delaware, as he did one weekend earlier this month.

For Ryan, it’s meant practice sessions in Washington, as well as his hometown of Janesville, Wis.

The candidates are not only scrutinizing each other’s past speeches and issue positions but also their recent appearances. After Biden’s blistering critique of the GOP ticket in Iowa, Ryan studied a transcript of the event. Biden’s preparation also has included reviewing video of Ryan interviews and speeches.