Suddenly, qualifying for Connecticut’s voluntary system of publicly financing campaigns, the Citizens’ Election Program, is make or break for candidates in the race for governor. And making the cut is proving difficult.

Just ask Tom Foley. His application will be considered today for the third time, bolstered by additional qualifying contributions he submitted since last week.

Or you could ask John P. McKinney. The Senate Republican leader and gubernatorial candidate acknowledged last week he was unable to raise the $250,000 in qualifying funds by himself, so he is pooling his contributions with a running mate, David M. Walker.

Danbury Mayor Mark Boughton ended his campaign for the Republican nomination for governor two weeks ago, conceding he could not qualify.

Foley quickly raised more than $250,000, but he still is having his problems. The GOP convention-endorsed candidate for governor is pursuing public financing this year after largely self-funding his first campaign four years ago. But his application has yet to be approved after two tries.

Not all his qualifying contributions have met the standards of the so-called “clean elections” program, which was created after Gov. John G. Rowland resigned 10 years ago in the face of an impeachment inquiry and a federal criminal investigation into his relationship with state contractors.

The CEP has changed the political landscape in Connecticut.

Here is how it works.

How do they qualify?

To obtain public financing, a major-party candidate must meet two tests: Qualify for the ballot and demonstrate broad public support by raising a threshold amount in small-dollar contributions, anywhere between $5 and $100.

There are a few wrinkles. For a statewide candidate, 90 percent of the qualifying money must be raised in Connecticut. (Legislative candidates have similar district-related standards to meet: 150 local contributions in a House race, 300 in a Senate contest).

Principals of state contractors or prospective contractors cannot make qualifying contributions.

Neither can children under age 12. (Yes,  they can exercise their First Amendment right to write a check at 12, even if they can’t vote until 18.)

What do they get?

That depends. For major-party candidates for statewide office, it’s pretty straight forward. They get the amounts below.

* Those offices are lieutenant governor, secretary of the state, comptroller, treasurer and attorney general. Candidates for lieutenant governor can only get a grant for a primary. In the general election, one grant goes to the ticket of governor and lieutenant governor.

** The larger amount goes to legislative candidates in districts dominated by one party. The theory is the primary is tantamount to the election in those districts.

How about minor party candidates?

Theoretically, they can get public grants awarded on a sliding scale, based on their ability to show public support. In reality, it’s a tough road.

First, a little background about what it means to be a major party. Contrary to popular belief, Democrats and Republicans are not guaranteed major-party status.

A major party in Connecticut is one defined as winning 20 percent of the vote in the previous election. In the 1990 race for governor, which was won by an independent, Lowell P. Weicker Jr., the Democrats came perilously close to losing major-party status. Democrats of a certain age still shudder at the memory.

Minor-party candidates are eligible for general-election grants if their party received a certain percentage of the vote in the previous election for that office or they collect an equivalent number of petition signatures.

To get equal treatment with the major-party nominees, a petitioning candidate would have to collect signatures equal to 20 percent of the votes cast in the previous election for that office.

Here’s the math: with 1.1 million votes cast for governor in 2010, that means collecting 222,000 signatures to obtain a full grant in 2014. Most political operatives would say that is impossible. That’s the bad news for a minor-party candidate.

The slightly better news is that lesser grants can be obtained by hitting lesser petitioning thresholds. Gathering signatures equal to 10 percent of the votes cast in the previous election earns a one-third grant; 15 percent gets a two-thirds grant. That is still a hard lift.

Here is what Jonathan Pelto, a petitioning candidate for governor, must do in 2014 to get some public financing: He needs a minimum of 111,000 signatures to collect $2,166,800. Is that doable? Pelto says he expects to opt out of the voluntary system.

How does it work for those who opt out?

If they can afford it, they can self-fund. There is no limit on what candidates can spend on their own campaigns.

Ned Lamont spent $9.65 million in 2010, mostly his own money, in a losing campaign for the Democratic nomination for governor. The same year, Tom Foley spent $12.8 million, including $11 million of his own money.

Gov. Dannel P. Malloy, who already has qualified this year, beat both of them with public financing.

If they can’t afford to self-fund, candidates still can raise money from individual donors and political committees, as was the case prior to the Citizens’ Election Program.

Individuals can give maximum donations of $3,500 to a candidate for governor. The state parties can give up to $50,000. Political committees formed by two or more individuals, labor unions or business entities can give $5,000.

What are the status of the statewide candidates?

Every Democrat has applied except Treasurer Denise Nappier, who still is working on raising $75,000 in qualifying contributions.

Grants have been approved for Malloy and Lt. Gov. Nancy Wyman, Secretary of the State Denise Merrill and Comptroller Kevin Lembo. Attorney General George Jepsen’s application is pending.

Among Republicans, Foley and McKinney have applied for funding, as have all three candidates for lieutenant governor: Penny Bacchiochi, Heather Bond Somers and Walker.

Grants have been approved for Bacchiochi and Timothy Herbst, the nominee for treasurer.