For years, political campaigns have tried to connect with their supporters through "voter identification."

Campaigns need to understand who their supporters are, and most ideally, why. Smart campaign strategy and spending decisions rely on strong voter identification to know how much support exists, and whether it's firm or wavering.

Once you know who your supporters are, you can make sure they vote. And in the case of voters who don't support you, there's a strategy you can use on them too.

How does voter identification work?

In modern campaigns, paper lists of party members, donors and supporters have been replaced by databases.

Electronic records are easier to update and share across larger numbers of campaign workers. Large, national databases are replacing the use of local lists, although individual ridings may still maintain and exchange their own informal records.

National political party databases, such as the Constituent Information Management System (CIMS) used by the Conservative Party, or NDP Vote and Liberalist, the custom systems used by the opposition parties, can identify not only the party's own supporters, but also non-supporters.

A well-researched and frequently-updated party database may be so powerful it can flag exactly where each party's potential voters live in a given neighbourhood.

P.O.V. Who would you tell about your political preferences? Take our poll.

But that database is only as accurate as the quality of the information input into the system. In reality, much of it comes from volunteers, and not everyone is willing to tell a telephone or door-to-door canvasser whom they support.

Databases can be built on publicly-available information, such as the Elections Canada voters' list (which is updated for every election, but does not contain phone numbers) or public telephone directories.

Campaigns also collect information themselves. Supporters may provide information when they register at political websites.

Professional call centres are sometimes hired to update voter identification databases more efficiently, to prevent the inconsistencies of volunteer efforts based on door-to-door or local telephone canvassing.

What's in a voter database?

In the beginning, campaigns collected basic information like names, addresses and telephone numbers.

Particularly valuable now are digital contact information such as email addresses or Twitter accounts, to allow for very inexpensive direct messaging.

Today, the limits to the information collected are endless, including credit card information (useful for financial donations), birthdays and anniversaries (useful for customized greetings), religious faiths and ethnicities (useful for targeting holiday or other custom messages, including ones in native tongues), or even details about someone's education history (public or religious school supporter? post-secondary grad?) or work life (union member? small business owner?) for targeting a specific appeal in the future.

Campaigns also may track what voters think about issues and policies, such as which voters support ending the gun registry or legalizing marijuana. Since support for a given issue may transcend party lines, a list of people supportive of an issue but not currently supporting a particular party can be a means of attracting new support if that issue heats up during an election.

What is GOTV? 'Get out the vote'

Once a candidate's supporters have been identified, it's critical that these voters exercise their franchise on election day.

A voter hands over a voter information card at a polling station before casting a ballot on May 2, 2011. Voter identification efforts are crucial to parties' attempts to get out the vote on election day. (Graham Hughes/Canadian Press)

In the 2011 federal election, only roughly six in 10 eligible Canadian voters cast a ballot. With that many voters staying home, it's critical to make sure "friendly" voters are the ones who actually show up at the polls.

Most political campaigns have someone, or often an entire team, assigned to "get out the vote" (GOTV).

This work may also be called "pulling the vote" on election day, a reference to campaigns literally or figuratively dragging supportive voters to the ballot box.

GOTV teams employ a variety of tactics. Some common techniques are:

Calling people who'd previously expressed support just before or on voting day to remind them to vote.

Circulating pamphlets in strategic places, making sure people know where and how to vote.

Offering free rides to polling stations (ideally, prioritized for identified supporters).

Using social media (email, Twitter, Facebook messages) to remind supporters to vote

Any of these efforts work better when they are focused on the voters most likely to cast a favourable ballot, instead of the general voting population. So the stronger the voter identification legwork is, the more effective the GOTV campaign can be.

What's voter suppression?

Here's the other side of the coin: While a campaign wants everyone who likes their candidate to vote, it helps when voters who'd support another candidate stay home.

Voter suppression is often related to what's referred to in campaigns as "going negative."

Not every voter can be won over. But if you can't win someone's support, attacking the credibility of the candidate that voter prefers could convince that voter to give up voting entirely and stay home.

Negative campaigns often result in low voter turnout, when many voters feel cynical about the usefulness of voting or their ability to make a change by casting a ballot. If all candidates appear to have weaknesses, it may cease to matter who wins for many in the general voting public.

A voter suppression campaign is successful if voters identified as unfriendly to a candidate are given reasons to tune out and stay away.

Beyond winning or losing campaigns, jurisdictions that reimburse or subsidize parties or campaigns based on the total number of votes received provide an additional motivation to hurt an opponent financially over the longer term.

While unsavoury at times, it is entirely legal to "go negative" with public criticisms of opponents to emphasize their flaws.

But beyond "going negative," some voter suppression tactics are also illegal.

In the 2011 election calls controversy, voters reported messages impersonating Elections Canada, which is against the law.

Impersonating an opponent's campaign, while not strictly illegal, is certainly unethical and not consistent with honest, fair play.

It's not uncommon for reports to surface during elections at all levels of candidates misrepresenting each other's statements or track records. Lies and dirty tricks are as old as politics itself, although in 2011 all parties denied using them.

In the 2010 gubernatorial race in Maryland, the Republican candidate hired a consultant who used deliberate vote suppression tactics, phoning voters in targeted African-American areas to tell them that the Democrat had already won and there was no need to vote, when in fact the polls hadn't closed yet. The campaign manager was convicted of fraud earlier this month.

Canadian voters are saying now they received incorrect polling location information for the May 2 vote, which could have delayed or even prevented some from casting a ballot. This kind of misdirection risks denying a voter his or her fundamental right to vote.

The biggest gamble in negative campaigning or vote suppression is that even legal "dirty tricks" may reflect badly on the campaign that chooses to employ them, risking one's reputation in the eyes of the very support that campaign needs to win the day.