The chairmen of the two House campaign committees took to the airwaves Sunday morning, arguing the case on “Fox News Sunday” for why their party is better equipped to pick up seats in November.

Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.) ended the broadcast by invoking the names of the likely presidential nominees, Sens. John McCain (R-Ariz.) and Barack Obama (D-Ill.), by urging National Republican Congressional Committee Chairman Tom Cole (Okla.) to agree to a ban on outside groups advertising in Congressional races.

Van Hollen said the campaign committees should ask outside political groups to refrain from pouring millions of dollars into third-party ads and should tell their donors not to contribute to the groups that place such ads. Both Obama and McCain have expressed squeamishness with the influence outside groups have on elections.

While House Democrats have an overwhelming financial advantage over their Republican counterparts, with more than six times as much cash on hand, Van Hollen and his lieutenants have openly worried about the influence of the conservative group Freedom’s Watch, and its possible ability to pour millions of dollars in advocacy ads into competitive Congressional districts.

Cole was not given time on the Fox broadcast to respond to Van Hollen’s proposal, but House Republicans in general have said little about Freedom’s Watch and other conservative groups that could potentially play in House races — in part to avoid the appearance of coordination with the groups.

During the rest of their 15-minute joint appearance on the program, Cole and Van Hollen essentially repeated the talking points they have used over the past several months.

On the heels of three recent special election losses in formerly strong Republican districts, Cole conceded that the House GOP faces “a challenging landscape.” But he expressed optimism that the party’s prospects for gains would improve when the general election is at full tilt and the issues are defined by the presidential campaigns.

“Once we’re in the presidential election, the dynamic changes,” Cole said.

Van Hollen acknowledged that Congressional approval ratings are low, but said that is largely a function of the House Republicans’ record during the dozen years they were in the majority, and argued that voters appreciate the changes Democrats are trying to make.

“The old Congress was the Congress that essentially turned the people’s house into the auction house,” Van Hollen said.