REAGAN HAS BEEN climbing back into contention since his Labor Day gaffe of criticizing Carter for opening his campaign in the "Klan center" of Tuscumbia. He has the backing of the Moral Majority and other active conservative groups, and trailed by only 8 points in a recent Birmingham Post-Herald poll and by 5 points in a recent private GOP poll. Carter has solid support from black voters and is still narrowly favored to hold the state.

Public Service Commissioner Jim Folsom Jr. (D), 31, the son of the former governor and primary victor over freshman Sen. Donald Stewart (D), finds himself in a very close race for the Senate with retired Adm. Jeremiah Denton (R), 56, the Vietnam POW hero and Moral Majority favorite. Folsom started out with a name recognition edge, but Denton has outdistanced him in finances and TV exposure and leads by 2 to 4 points in both the Post-Herald and private polls.

Rep. John Buchanan (R), a moderate who was upset in the GOP primary by the Moral Majority candidate, Birmingham insurance man Albert Lee Smith Jr. (R), has lost his court battle to run as an independent and has given up hopes of mounting a write-in campaign. Smith is favored over City Councilman W. B. (Pete) Clifford (D), a Methodist minister whose own conservative views separate him from the normal Democratic constituency support. ARKANSAS (6)

CARTER LEADS the incumbents' parade in Arkansas, but his margin is shakier than the others'. The final poll of KATV and the Robert D. Doubleday Co. had Carter 49, Reagan 39 and Anderson 5. The poll showed Carter's support among blacks holding firm and his overall margin declining only slightly.

Gov. Bill Clinton (D), 34, has endured stiff criticism of his administrative practices from Frank D. White (R), 46, the Little Rock savings and loan executive who opposes his second-term bid. While the attack may tarnish Clinton's glittering national reputation, it should not cut short his political career.

Sen Dale Bumpers (D), 55, is having an easier second-term campaign against Bill Clark (R), 37, a Little Rock investment banker, and the two incumbent House members of each party are safe. i FLORIDA (17)

A POLL RELEASED yesterday by four Florida newspapers confirmed the worst fears of the Carter camp: This vital battleground, which Carter has not lost in any primary or general election, appears headed to Reagan. He led 45-39 among all voters and 55-38 among the most likely voters, having gained among Hispanics and moved up to 30 percent among south Florida Jews, while holding his strength in the conservative Panhandle. Top state Democrats are stumping hard for Carter and say he has a chance, but the odds against him are heavy.

The newspapers' survey released Saturday showed former state public service commissioner Paula Hawkins (R), 53, running 10 points ahead of State Insurance Commissioner Bill Gunter (D), 46. Gunter defeated freshman Sen. Richard Stone (D) in a bitter runoff and the wounds -- especially in Miami -- have not healed.

There are two open House seats -- one in each party -- that look tempting to the opposition. The GOP has designs on an East Coast seat where Fort Lauderdale Mayor Clay Shaw (R) is challenging former state representative Alan S. Becker (D), who ousted freshman Rep. Edward J. Stack (D) in the primary. Across the state, there is the reverse situation. David Best (D) is driving for a win over fellow attorney Bill McCollum (R) in the district where Rep. Richard Kelly (R), indicted in Abscam, lost in the primary. A split is possible. GEORGIA (12)

DESPITE REAGAN RALLIES in Plains and other GOP shenanigans, Carter likely will win his home state with more than 60 percent of the vote.

The surprise is that Mack Mattingly (R), 49, the former state GOP chairman, has thrown a scare into Sen. Herman E. Talmadge (D), 67, seeking his fifth term. Talmadge, who was denounced by the Senate in 1979 for financial misconduct and who admitted to alcoholism in a splashy divorce case, relaxed after winning renomination in a tough primary and runoff. But Mattingly's aggressive TV campaign, hitting Talmadge for absenteeism, tightened the race and pushed Talmadge back onto the trail. Talmadge had used the ultimate epithet against the Indiana-born Mattingly, calling him a "carpetbagger," and while the margin may be close, defeat of the incumbent would be a major upset.

The House roster will have familiar names, except that State Rep. Charles F. Hatcher (D) will replace Rep. Dawson Mathis (D), who lost to Talmadge in the Senate primary. KENTUCKY (9)

SEVERAL OCTOBER samplings suggest that Carter has gained the upper hand in what once was a tough struggle for control of this state. A strong black vote, growing support in the eastern Kentucky coal regions and -- most important -- strong backing from Gov. John Y. Brown (D) and Sen. Wendell H. Ford (D) give Carter a narrow edge.

Ford, 56, has no problems in his second-term campaign against former state auditor Mary Louise Foust (r), 70. The only change expected in the House is the replacement of retiring Rep. Tim Lee Carter (R) by Harold (Hal) Rogers (R), a moderate lawyer who tried unsuccessfully a year ago for lieutenant governor. LOUISIANA (10)

REAGAN HAS CAMPAIGNED in Louisiana half a dozen times this year, most recently on Oct. 30, in a bid to switch its votes from Carter's column. Carter's Oct. 21 visit to New Orleans was less splashy than the rally that helped him win in 1976, but the combination of black votes and ex-governor Edwin Edwards' (D) campaigning among the Cajuns for a president he often criticized have kept Carter in contention. Energy Secretary Charles Duncan flew in Friday to announce Carter plans a $400 million dredging project on the Mississippi, which Gov. David Treen (R) called "a Halloween prank." The voters will decide whether it's trick or treat in this tossup state.

Sen. Russell B. Long (D), 61, won his sixth full term, and all but one of the eight representatives were reelected in the September all-party primary. Rep. Claude (Buddy) Leach (D), whose first-term victory in 1978 was clouded by vote-buying scandals, is testing his rural support against the urban base of Buddy Roemer (D), a Harvard-trained computer executive with the backing of the Republican who narrowly missed the runoff. MISSISSIPPI (7)

CARTER HAD a good stop here Friday and has the all-out backing of Gov. William Winter (D). But GOP polls show Reagan has a huge lead among white voters and Carter's hopes for a big black turnout may be damaged somewhat by Reagan's support from black leader Charles Evers. Mississippi ranks as one of Carter's likelier Dixie losses.

Recent publicity on the details of the incident that led freshman Rep. Jon C. Hinson (R) to admit last summer his involvement in Washington's homosexual world have created fresh problems for his campaign. But local observers say the vote split between Britt R. Singletary (D) and black independent Leslie B. McLemore could enable Hinson to hold on against the odds. NORTH CAROLINA (13)

BACKED BY the strong organization of Gov. James B. Hunt Jr. (D), Carter appears to have held his steady lead over Reagan. Hunt, 43, is a heavy favorite to win a second term over State Sen. I. Beverly Lake Jr. (R), 46.

The hot fight is the Senate race between freshman Sen. Robert Morgan (D), 55, and John P. East (R), 49, a college professor and polio victim. East, like Lake, is a political protege of Sen. Jesse Helms (R), whose fund-raising has financed a late TV blitz for the challenger. Morgan has not been able to match it, but remains a slight favorite in a narrowing race.

The closest House race pits sophomore Rep. Lamar Gudger (D) against businessman William M. Hendon (R) in a district with real Republican strength. Six-term Rep. Richardson Preyer (D), who usually does not have a strong challenger, has one this year in Eugene Johnston (R), a lawyer-businessman. OKLAHOMA (8)

CARRYING THE STATE for Reagan has never worried Republicans, but holding the seat of retiring Sen. Henry Bellmon (R) still does. Andy Coats (D), 45, the former district attorney of Oklahoma County, leads the polls in his home area, where Republicans normally need a good majority. But the GOP has one poll showing State Sen. Don Nickles (R), 31, narrowly ahead. An independent Democrat from Oklahoma City, former attorney general Charles Nesbitt, 59, does not appear to be cutting deeply into Coats' vote but is still worrisome to his chances. Nickles has the Moral Majority's support, but the Oklahoma Conference of Churches last week condemned that group's intervention in politics. The race is a tossup.

The GOP has a chance to pick up the seat of retiring Rep. Tom Steed (D). Retired Navy Capt. Howard Rutledge (R), a Vietnam prisoner of war, is battling Norman lawyer Dave McCurdy (D). SOUTH CAROLINA (8)

REAGAN'S CONSERVATIVE APPEAL, combined with a smooth-working organization have kept this state, which was easily Carter's in 1976, highly competitive this time. Bush was back yesterday to give it a boost, but the betting is that Carter's Friday visit, plus black voters' interest in several local contests, plus the backing of Gov. Dick Riley (D) will pull Carter through to a narrow win. A Columbia television station poll had Carter 2 points up last week.

Sen. Ernest F. Hollings (D), 58, has no real worries in his third-term contest with former state representative Marshall T. Mays (R), 56. Rep. John W. Jenrette Jr. (D) considered dropping out of the race after his Abscam conviction but instead is battling uphill against attorney John L. Napier (R). Republicans think they may also gain the seat of retiring Rep. Mendel J. Davis (D) but the likelihood of a big black vote may boost Charles D. (Pug) Ravenel (D) over State Sen. Thomas F. Hartnett (R). TENNESSEE (10)

BOTH PARTIES had pre-debate polls showing Carter running 3 to 7 points ahead, and the Reagan camp conceded the president the last word -- a Friday appearance in Memphis. The margin will not resemble the 1976 landslide, but Tennessee looks like a Carter stronghold in an otherwise shaky South. No change is expected in the House delegation. TEXAS (26)

REAGAN'S PERSONAL POPULARITY is bolstered by the home-state appeal of Bush, the near-fanatic support of Gov. William Clements (R) and a $3 million state GOP phone bank operation. Carter's energy, defense and farm policies have caused some defections among traditional Democrats, but his organization has made a heroic effort to compensate by mobilizing a huge turnout of black and Chicano voters. A pre-debate Democratic poll showed a virtual standoff, but last week's surge lifted Reagan 7 points ahead in his own polls, and the odds are clearly against Carter repeating his narrow 1976 victory.

House Majority Leader Jim Wright (D) likely will withstand the free-spending challenge of Jim Bradshaw (R), former mayor pro tem of Fort Worth, in the state's premier House race. Party efforts to boost vote turnout may help other threatened incumbents: Rep. Jim Mattox (D) in a rematch with attorney Tom Pauken (R); Rep. Bob Eckhardt (D) vs. attorney Jack Fields (R), and Rep. Ron Paul (R) vs. attorney Mike Andrews (D). Former state senator Ralph M. Hall (D) is favored over businessman John H. Wright (R) for the seat of retiring Rep. Ray Roberts (D), and State Sen. William Patman (D) is a narrow favorite over pediatrician Charles L. Concklin (R) for the vancancy caused by the retirement of Rep. Joe Wyatt (D). VIRGINIA (12)

DESPITE BRAVE TALK from the Carter side about capturing the only Southeastern state he lost in 1976, Reagan seems secure. Published polls put him 5 to 9 points up, and the endorsement of Sen. Harry F. Byrd Jr., an independent, and the work of a vastly superior state GOP organization could broaden that margin.

The GOP seems sure to pick up the seat of retiring Rep. David E. Satterfield (D), with former Richmon mayor Thomas J. Bliley Jr. (R) strongly favored over John A. Mapp (D), a retired college dean. A second turnover could come in Northern Virginia, where Rep. Joseph L. Fisher (D) is in a tossup rematch with attorney-lobbyist Frank R. Wolf (R). Rep. Herbert E. Harris II (D) is holding a safer margin in his rematch with ex-Rep. Stanford E. Parris (R).