It's deadline day for Conservative leadership candidates - so who's in?

If you woke up this morning with a keen desire to be the next leader of the Conservative Party of Canada, you had only a few hours left to get your name in — along with the signatures of 1,000 party members and $25,000.

The first deadline for qualifying to be a candidate to replace Andrew Scheer as Conservative leader passes at 5 p.m. ET today. To be eligible, prospective candidates need to submit the signatures of 1,000 party members distributed across at least 30 ridings in seven different provinces or territories, along with the first $25,000 instalment of the $200,000 entry fee. If they also get a green light from the party's vetting committee, they're in.

At least, they're mostly in. The next eligibility deadline is Mar. 25. That one might prove to be a bigger challenge.

As of end of day Thursday, seven candidates had met the first eligibility requirements. In order of their approval by the party, they are:

• Peter MacKay, former minister of justice, foreign affairs and national defence in Prime Minister Stephen Harper's cabinet, Nova Scotia MP from 1997 to 2015 and the last leader of the Progressive Conservative Party of Canada.
• Erin O'Toole, former minister of veterans affairs, MP for the Ontario riding of Durham since 2012 and third-place finisher in the 2017 Conservative leadership race.
• Leslyn Lewis, lawyer, unsuccessful Conservative candidate in the 2015 federal election in the Ontario riding of Scarborough–Rouge Park.
• Marilyn Gladu, MP for the Ontario riding of Sarnia–Lambton since 2015.
• Derek Sloan, MP for the Ontario riding of Hastings–Lennox and Addington since 2019.
• Jim Karahalios, anti-carbon tax activist who filed a lawsuit against the Ontario PC Party alleging the contest for the provincial party presidency had been rigged against him.
• Rick Peterson, businessman, finished 12th in the 2017 leadership race.

This list of eligible candidates could still grow. A number of other figures have said they plan to run, among them former Conservative staffers Rudy Husny and Richard Décarie. Both have told CBC News they have the signatures and entry fees they need, and are awaiting approval by the Conservative Party.

In addition to the initial $25,000 entry fee and 1,000 signatures, both MacKay and O'Toole also have submitted another 1,000 signatures each, another $25,000 entry fee instalment and a $100,000 refundable compliance deposit. This classifies them as "authorized contestants," which gives them access to the current and historical database of Conservative Party members.

That's an important step for all candidates, as access to that list makes it much easier to raise money and solicit support from within the party. The initial $25,000 entry fee comes from a candidate's personal resources. To get to the second tier, candidates need to demonstrate their fundraising prowess without the aid of a list of party members.

The third and final step requires another batch of 1,000 signatures and the final entry fee instalment of $150,000, all to be submitted by Mar. 25. Only candidates who clear that third hurdle will get their names on the ballot. In total, those candidates will have obtained the signatures of 3,000 members and submitted $300,000 to the party — making this the most expensive political leadership contest in Canadian history.

Getting there won't be easy. Of the 14 candidates who ran for the Conservative leadership in 2017, only nine were able to raise at least $300,000 over the course of a much longer race. On average, it took them 143 days to raise that sum. The final deadline is only 27 days away.

The list of "approved applicants" might not be complete until early next week. Any prospective candidates who submit their entry fees and signatures before Thursday's 5 p.m. ET deadline still need to have those signatures verified and will have to pass a vetting interview with the party's leadership committee — a process that could take several days.

On Wednesday, the Conservatives announced they would hold two official leadership debates. The first, in English, will take place in Toronto on Apr. 17, the last day that Canadians can join the party and be eligible to vote. A French-language debate will be held in Montreal on Apr. 23.

The results of the leadership race will be announced June 27 in Toronto.