Political comebacks are the order of the day as voters go to the polls in 10 states today in the busiest day of primary balloting this year.

In Arizona, the season's most improbable bid for a second chance is being attempted by Evan Mecham, who is seeking the Republican nomination for governor -- the job from which he was removed by impeachment two years ago as a result of scandals and an abrasive governing style.

Polls in the final week of the campaign showed Mecham running second in the five-man GOP field to developer Fife Symington, but some analysts speculated that in a low-turnout primary Mecham could score a surprise. The winner will face Phoenix Mayor Terry Goddard, who has only token opposition in the Democratic primary. Incumbent Gov. Rose Mofford (D), who took over after Mecham's removal from office, chose not to seek a full term.

In Vermont, former four-term governor Richard Snelling, trying to win his job back after a six-year absence, is the heavy favorite in the Republican primary -- and in November as well, when he is expected to face Democrat Peter Welch. The incumbent governor, Democrat Madeleine Kunin, chose to retire after three two-year terms.

In New Hampshire, former senator John A. Durkin (D), who lost his Senate seat to Republican Warren B. Rudman in 1980, appeared to have the momentum going into today's Democratic primary against businessman John Rauh and Nashua Mayor James Donchess. The winner is expected to face Rep. Robert C. Smith, the heavy favorite for the GOP nomination for the seat being vacated by retiring Sen. Gordon J. Humphrey (R).

In Connecticut, the comeback candidate -- former senator Lowell P. Weicker Jr. -- is not on any primary ballot today but is the favorite to win the governorship this fall. Weicker, a maverick Republican who has frequently warred with his own party, is running as an independent. Rep. John G. Rowland (R) is the endorsed Republican candidate and has no primary opposition. Democrats will choose between Rep. Bruce Morrison and state Rep. William Cibes in a race that took a nasty turn in its closing days as each candidate impugned the other's integrity.

In Minnesota, the comeback candidate is the 10-year incumbent governor, Rudy Perpich, whose poll standings had sunk to such lows earlier this year that political observers in the state were writing him off. But polls published last week showed him with a narrow lead in the Democratic primary over former state commerce commissioner Mike Hatch, who has the support of abortion-rights groups. In the Republican primary, polls show state auditor Arne Carlson is leading businessman Jon Grunseth, the candidate endorsed by the state Republican Party, and two others.

In Rhode Island, another embattled governor, Republican Edward D. DiPrete, is heavily favored over talk show host Steve White. But polls show he is the underdog against all three Democrats who have been engaged in a hard-fought primary: Providence Mayor Joseph R. Paolino Jr., Warwick Mayor Francis X. Flaherty and businessman Bruce Sundlun, the 1986 and 1988 Democratic nominee.

Primaries are also being held today in New York, Wisconsin, Utah, Maryland and the District of Columbia.