– House Speaker Paul Ryan’s announcement Wednesday that he will forgo re-election and relinquish his gavel in January triggers an unpredictable and unexpectedly early scramble to determine who will succeed him atop the Republican hierarchy.

Ryan’s departure would appear to clear the way for lower-ranking GOP leaders, including Majority Leader Kevin McCarthy of California and Majority Whip Steve Scalise of Louisiana, to move up the ladder. But key uncertainties, starting with whether Republicans will be able to maintain their House majority, could keep the race unsettled for months.

“Everybody will start jockeying for position immediately,” said Rep. Mark Meadows, R-N.C., chairman of the House Freedom Caucus. “They won’t wait for nine months.”

Still, it could be months before the derby truly takes shape. One big unknown is what exactly the House Republican Conference will look like come January 2019: At least 38 currently serving GOP members will not return next year, and dozens more incumbents are at risk of losing their seats. In the meantime, potential leaders could be judged by their peers based on the size of their fundraising totals and campaign schedules.

“I think that everybody’s going to help us win the majority, and then there’ll be a race for speaker assuming we get the majority,” said Rep. Steve Stivers, R-Ohio, chairman of the National Republican Congressional Committee.

McCarthy and Scalise, in the No. 2 and No. 3 spots respectively, hold a key advantage in any leadership showdown: relationships.

McCarthy has assiduously developed close ties with GOP members, personally recruiting dozens of them to run in the landmark 2010 Republican landslide, and he has cannily adjusted to a shifting political climate in recent years. More recently, he has cemented those relationships with campaign cash, raising nearly $9 million already this year — most of which gets doled out to vulnerable members.

Scalise, as the lead Republican vote counter, is the member of GOP leadership who most rank-and-file members interact with on a routine basis, and his Capitol office suite tends to be a hub for lawmakers when the House is in session. Like McCarthy, he is a gregarious backslapper with a sharp memory and shrewd instincts.

But his personal saga of the past 10 months — being shot in June by a would-be assassin who targeted Republican lawmakers practicing baseball, nearly dying on an operating table and enduring a grueling recovery to return to work last fall — has placed him in a new light and could allow him to leapfrog McCarthy under the right circumstances.

It is unusual in recent decades for a congressional leadership scramble to play out over an extended period. Not since Tip O’Neill, D-Mass., announced his 1986 retirement two years in advance has a House speaker served an extended period as a lame duck.