What are poll watchers and what do they do?

The comments fit into a pattern for the President, who has made repeated unproven claims that Democrats will commit fraud to win the election and has even suggested he would deploy law-enforcement officials to monitor the polls.

But that's not how poll watching works, experts say.

Federal and state laws prevent intimidation of voters, and state statutes set out specific guidelines for who can serve as poll watchers and how they must conduct themselves on Election Day.

Here's how it works:

What can poll watchers do?

Poll watchers, as the name implies, are expected to watch or observe what happens at polling places. Their primary job: Help ensure that their party has a fair shot at winning. Both parties do it.

But poll watchers can't interfere in any way with the actual voting process.

They can closely monitor the administration of the election to ensure that votes are counted accurately. And in some states, poll watchers can also challenge an individual voter's right to cast a ballot. Partisan poll watchers, however, must conduct those challenges through official poll workers and cannot stop or otherwise try to interfere with someone trying to vote.

Even if a poll watcher challenges an individual voter -- for instance, by arguing that the person's name doesn't appear on the local voting rolls -- states often allow that person to cast a "provisional" ballot to be counted later once his or her right to vote has been verified.

Poll watchers also can help turn out the vote by counting the voters who have cast ballots and helping their respective candidates track which potential supporters haven't yet voted. That helps campaigns mount last-minute Election Day efforts to get those voters to cast their ballots before polls close.

If voters sees questionable actions or feel intimidated, they should seek the help of the trained election workers at the precinct, experts say.

Who can be a poll watcher?

The requirements vary by state, but poll watchers generally must be registered voters, according to the National Conference of State Legislatures, which has tracked poll-watching laws in each state.

In some cases, they must be registered voters in the specific precinct or county they are monitoring.

In Pennsylvania, for instance, poll watchers must reside in the county in which they are watching the polls. The Trump campaign has gone to court to try to overturn that law, which makes it harder for Republicans to find enough poll watchers to deploy to every polling place in Democratic strongholds such as Philadelphia.

And there are safeguards against random voters taking it upon themselves to serve as poll watchers. Some states, for instance, require that party officials or candidates designate who will observe polls.

In North Carolina, where Trump encouraged rallygoers this week to watch the polls on his behalf, the power rests with the chairperson of each county's political party to designate observers in each polling place.

They also must give the chief election judge in each polling place a list of designated observers -- a further safeguard against a stray voter trying to police activity within a polling place.

Laws in many states also create buffer zones around polling places, another measure to protect against voter intimidation.

Why is this controversial?

Federal law bars the deployment of armed federal officials to the vicinity of polling places, and the President does not have the authority to command local law-enforcement officials to do anything.

But misleading rhetoric about voter fraud, much of it coming from the President, and some not-too-distant history have raised fresh concerns about the potential for voter suppression.

More than three decades ago, a GOP program that sent armed, off-duty law-enforcement officials to minority polling places in New Jersey sparked allegations of voter intimidation and resulted in a consent decree that sharply restricted the national party's poll-monitoring activity.

That decree has expired, and November's election marks the first presidential race since 1980 in which the Republican nominee and the Republican National Committee can work together on poll-watching.

Freed from those decades-old legal restraints, the Trump and RNC campaign say they plan to recruit tens of thousands of poll watchers to battleground states. An RNC official told The Washington Post that law-enforcement officials are not part of the party's poll-watching efforts.

The overheated rhetoric has, nonetheless, sparked worries about voter intimidation.

Richard Hasen, an election-law expert at the University of California at Irvine, told CNN last month that he's worried about "rogue Trump supporters who might take matters into their own hands and go to polling places with Trump's claims of fraud and voting problems."