Washington Senate Majority Leader Rodney Tom (D). (Screenshot: senatedemocrats.wa.gov)

There are 25 Democrats in the Washington State Senate and 24 Republicans. Simple math would suggest Democrats should control the chamber. But only two Democrats hold leadership positions — the two Democrats who decided to caucus with Republicans last year to form a working bipartisan majority.

The two Democrats, Rodney Tom, of Medina, and Tim Sheldon, who represents a conservative part of the Olympic Peninsula, have proven more powerful than the Democratic majority in the state House, and more powerful than Jay Inslee, the Democratic governor just a year into his first four-year term. That means Tom and Sheldon will drive much of the agenda in this year’s legislative session, which begins Monday.

The Seattle Times’ Andrew Garber previews the session:

Their priorities include pushing through a series of laws, including changes to the state’s workers’ compensation system and state pensions.

Tom also says the Legislature should act on a transportation tax package this year.

But this may be the last year Tom has the power to drive the agenda. When he and Sheldon joined Republicans to take control of the chamber during budget negotiations in 2012, Republicans held 23 seats; the two Democrats gave them just enough votes to wrest control. Last fall, Republicans won a critical special election in a seat formerly held by U.S. Rep. Derek Kilmer (D), giving them 24 seats. If they win one more, the GOP has plans to give Tom his walking papers.

“The minute we pick up one more seat, we will elect a Republican as majority leader. There’s no question about that,” state Sen. Don Benton (R) told the Times.

One of the state’s top priorities will be keeping one of its largest employers, Boeing, happy. In a special session in November, the legislature gave Boeing the largest corporate tax break in U.S. history as part of a bid to ensure an assembly line for the 777X long-haul aircraft would stay in the state. Boeing also wants to see big new investments in transportation and infrastructure projects, a piece of Inslee’s agenda that didn’t move through the special session.