Congressman Bill Cassidy spent Monday knocking on doors in the Baton Rouge subdivision where he grew up.

Three-term U.S. Sen. Mary Landrieu rallied union members in Baton Rouge and Rob Maness ate ice cream in north Louisiana.

All three major candidates for the U.S. Senate spent a frantic Monday looking for just enough support to win Tuesday’s election outright, an outcome few think is likely.

Polls will be open from 6 a.m. to 8 p.m. Tuesday. State government is closed, as are most public schools. But many private and parochial schools will be open.

Because of the role Louisiana may play in deciding which party controls the Senate, voters could see national and international news media at the polls, monitoring the election.

The Senate race may be the headliner, but voters across Louisiana are choosing all six representatives to the U.S. House and deciding 14 amendments to the state constitution. Voters heading to the polls across the Baton Rouge metro area will decide who can claim district judgeships, school board seats and scores of municipal positions — from mayors to council members.

Only one district attorney in the metropolitan area picked up a challenger: Incumbent Sam D’Aquilla faces David Opperman to be the top prosecutor in East and West Feliciana parishes.

On the other hand, many judges on Baton Rouge’s 19th Judicial District Court are facing opponents for their seats, and one open position on the bench has drawn four candidates.

The East Baton Rouge Parish School Board is equally competitive, although there are fewer overall seats in contention, as the board this summer decided to shrink its size from 11 seats to nine.

In many parishes, voters will need to weigh in on property tax propositions, such as renewals for recreational facilities, the drainage system and library in West Baton Rouge Parish or East Baton Rouge’s tax to control the populations of mosquitoes and rodents.

In Ascension Parish, voters will consider a proposal for a new 10-year recreation tax, estimated to bring in about $58 million, that backers say is needed to upgrade the park system in a growing parish and opponents say is unnecessary.

Also in Baton Rouge, U.S. Rep. Cedric Richmond, D-New Orleans, faces nominal opposition in his re-election bid for the 2nd Congressional District, which covers a large swath of East Baton Rouge Parish and many of the river parishes.

A much more competitive race is expected in the 6th Congressional District, Baton Rouge’s other congressional seat. Former Gov. Edwin W. Edwards, 87, faces 10 other candidates in the hotly contested race. The 6th District covers much of southeast Baton Rouge and its suburbs, down to the western suburbs of New Orleans and over into Houma.

Edwards, as the best-known of the three Democrats running in an overwhelmingly Republican district, is expected to find enough votes to make the Dec. 6 runoff.

It’s a tight race among the seven Republicans, four of whom have raised significant funds and show up neck and neck on various polls. They are state Sen. Dan Claitor; Garret Graves, the top coastal adviser in the Jindal administration; and Paul Dietzel, a 28-year-old entrepreneur, all from Baton Rouge, as well as state Rep. Lenar Whitney, of Houma.

In the headliner Senate contest, Landrieu pushes the clout she has accumulated over the past 18 years. She is chairwoman of the Senate committee that oversees energy policy. Republican Cassidy claims unseating the Democrat will lead to a new era that will roll back the programs of President Barack Obama. Maness, a Republican running to the right of Cassidy, promises more conservative values in government.

Though Landrieu and the Democrats are pushing for an outright win Tuesday, the more likely scenario is a Dec. 6 runoff, probably with Cassidy, if the polls are to be believed.

Hanging over the race from a national perspective is whether the Republicans will win control of the U.S. Senate, as they have in the U.S. House. The GOP needs to pick up six seats to gain a majority in the upper chamber of Congress and have targeted incumbent Democrats, like Landrieu, who were elected from states dominated by Republicans.

Handicappers said Monday that the GOP takeover was likely, with The Washington Post giving that outcome a 7 in 10 chance.

In another closely watched contest, incumbent U.S. Rep. Vance McAllister’s easy ride to re-election in the 5th Congressional District became bumpy when he was caught kissing a married aide.

He had run as a “family values” candidate and won the seat last year with the support of Monroe Mayor Jamie Mayo and the Robertson family who star in “Duck Dynasty,” the reality show on cable television. This fall, however, Mayo is running as the only Democrat and the Robertsons are backing Republican Zach Dasher, of Calhoun, a nephew of patriarch Phil Robertson, who says this time the candidate “has been vetted” by the family.

Other Republicans in the race include Dr. Ralph Abraham, of Mangham; Harris Brown, of Monroe; Ed Tarpley, of Alexandria; and Louisiana Public Service Commissioner Clyde Holloway, of Forest Hill.

The 5th District covers northeast and central Louisiana along with parts of the Florida parishes along the Mississippi border.

Secretary of State Tom Schedler calculates 52 to 53 percent of the state’s 2.9 million voters will turn out Tuesday. That’s more than the 44.2 percent in 2010, the last midterm election, which swept Republicans into control of the U.S. House, but less than the 67.9 percent in 2012, when President Barack Obama ran for his second term.

“I hope for 60 percent. But quite frankly, the data just doesn’t tell me that,” Schedler said.

About 1.3 million voters in 4,018 precincts will use about 10,000 voting machines to cast ballots Tuesday.

Each machine can handle about 20 voters an hour, he said.

“There are going to be lines,” Schedler said. “It’s one of the longest ballots we’ve seen.”

At 8 p.m. sharp, precinct officials will mark the end of the lines and allow those people still waiting to cast ballots.

“We may not finish voting until 8:30, maybe quarter to 9,” Schedler said, saying that the outcomes in tighter races may not be known until well after midnight.

Follow Mark Ballard on Twitter, @MarkBallardCNB. For more coverage of government and politics, follow our Politics Blog at blogs.theadvocate.com/politicsblog.