By CQ Politics staff

The Democratic officials who head up the party’s national campaign for U.S. House seats today showcased 50 of their candidates for Republican-held seats during the second day of the Democratic National Convention in Denver — with eight of them singled out for special attention in a press release sent out this afternoon.

All of these candidates were presented during a convention segment, which was scheduled for 4 p.m. local time (6 p.m. eastern), with Maryland Rep. Chris Van Hollen , chairman of the Democratic Congressional Campaign Committee Chairman (DCCC), moderating.

The following are capsule descriptions of those eight highlighted candidates, from the staff of CQ Politics, which closely follows and handicaps all 435 House contests. CQ Politics’ ratings for all House contests, including the competitive races in the No Clear Favorite, Leans and Favored categories, can be found here.

• John H. Adler, New Jersey, 3rd District: Adler, a longtime state senator, actually was aiming to run for the Senate in the 2008 election year. But the decision by veteran Democratic Sen. Frank R. Lautenberg to run for re-election this year at age 84 — and the coincidental decision by longtime southern New Jersey Republican Rep. H. James Saxton to retire — prompted Adler to set his sights closer to home.

Chris Myers, the Republican nominee, has advantages in the district’s longstanding (though not overwhelming) Republican lean and the endorsement he drew early on from the popular Saxton. But Myers, the mayor of Medford, is recovering from a bruising June primary that sapped his funds while Adler, unopposed for the Democratic nomination, stockpiled a sizable campaign treasury. CQ Politics rating: No Clear Favorite

• Joe Garcia, Florida, 25th District: The Democrats have typically given virtual free passes to a pair of Republican brothers who represent parts of South Florida in Congress: Mario Diaz-Balart , who is in his third term in the 25th District, and Lincoln Diaz-Balart , who is in his eighth term in the 21st District. In doing so, the Democrats were essentially yielding to the Republican-voting tendencies of the Cuban-American constituency, of which the Diaz-Balarts are part, which stem from the GOP’s identification with antipathy toward Fidel Castro’s communist regime in Cuba.

But Democrats of late have sensed some softening in the Cuban community’s Republican ties — and are challenging both brothers Diaz-Balart with Cuban-American Democrats this year.

Mario Diaz-Balart faces a challenge from Joe Garcia, former chairman of the Miami-Dade County Democratic Party, who also is former executive director of the Cuban American National Foundation. But the Republican incumbent maintains an edge in a district that went 56 percent for President Bush in 2004. CQ Politics rating: Republican Favored

• Debbie Halvorson, Illinois, 11th District: Halvorson, the majority leader in the Illinois Senate, is pursuing the seat left open by retiring seven-term Rep. Jerry Weller . She was regarded as one of the Democrats’ top recruits for a Republican-held seat — even before the original Republican nominee, local official Tim Baldermann, dropped out of the race just weeks after his victory in the Feb. 5 primary.

The GOP, which generally holds an edge in this district south of Chicago, rebounded by nominating concrete company executive Martin Ozinga, who quickly cut into Halvorson’s big fundraising head start. But Halvorson’s high political profile, big treasury and possible coattails benefits from Illinois Sen. Barack Obama ’s campaign for president give her at least a slight edge. CQ Politics rating: Leans Democratic

• Christine Jennings, Florida, 13th District:

Despite a Republican lean in this Gulf Coast district, Democrat Christine Jennings is waging a strong rematch bid against freshman Republican Rep. Vern Buchanan . Jennings, a retired banker, attracted national attention in the aftermath of the 2006 open-seat race, when she charged her 369-vote certified margin of defeat was the result of voting machine errors.

Buchanan again is facing inquiries about his past business history such as those that hindered his campaign two years ago. But the wealthy auto dealer is once again one of the best-financed candidates this year. CQ Politics rating: Leans Republican