Oregon’s Senate Democrats needed support from 16 of their 18 members to pass House Bill 2020, which would cap the state’s carbon emissions.

It became clear on Tuesday they’d come up short.

Sen. Betsy Johnson has been open about her opposition to the proposed cap-and-trade legislation, while Sen. Arnie Roblan also expressed doubts. Sen. Laurie Monnes Anderson had successfully pushed for some changes in the bill, and supporters were under the impression she planned to vote “yes.” Yet three well-placed Capitol sources affiliated with Democrats confirmed on Tuesday that Monnes Anderson was the third hold-out.

Here’s some background on the Democrats whose stances appear to have led Senate President Peter Courtney to announce the lack of necessary votes for the bill in hopes he could persuade Senate Republicans to move forward with other legislation before Sunday night’s end-of-session deadline.

Sen. Betsy Johnson, D-Scappoose

Johnson is a legislative veteran known for being blunt, business-friendly and unafraid to cross party lines. She is the daughter of Sam Johnson, a well-known Oregon lumberman and former Republican state representative.

Johnson had been clear this session that she opposed the cap-and-trade bill, saying on her weekly podcast that it had “the very real potential to cripple Oregon’s economy and to change our economic landscape, particularly in rural Oregon, in ways that we could not have imagined.”

During her nearly 15 years in the Oregon Senate, Johnson has taken more than $100,000 from timber interests and $20,000 from farmers. Nearly 70 percent of the $1.3 million she raised over the past decade came from corporations.

Johnson and Roblan are the only Democrats in Oregon’s Senate who have accepted campaign contributions from Koch Industries, the conglomerate owned by the conservative billionaires David and Charles Koch, who have worked to undercut action on climate change nationwide. Roblan and Johnson each have accepted $1,000 from the Kochs.

Johnson has also taken $1,500 from Kraft Foods, another company that landed on Oregon’s list of energy-intensive, trade-exposed businesses.

Sen. Arnie Roblan, D-Coos Bay

A former teacher and principal, Roblan previously served four terms in the House, during which he twice served as co-speaker. He had raised concerns about HB 2020, specifically about the bill’s impact on gas prices.

In addition to the $1,000 from the Kochs, Roblan has accepted $53,000 from timber interests during his tenure. Less than half of the campaign contributions he received came from corporations.

Roblan has also taken $1,500 from Ash Grove Cement, a vocal opponent of the bill that donated heavily to the Republican walkouts. He took $5,000 from Kraft and $1,000 from International Paper, another energy-intensive business.

Sen. Laurie Monnes Anderson, D-Gresham

Monnes Anderson, a retired public health nurse and former school board member, lists job creation among her top three priorities, along with health and education.

As The Oregonian/OregonLive reported last week, Monnes Anderson had been pushing for more concessions to offset House Bill 2020’s impact on electricity costs for Boeing, a large employer in her district.

Brad Reed, a spokesman for the environmental group Renew Oregon, said on Tuesday that the senator had “told us she was a ‘yes,’” but three well-placed Capitol sources affiliated with Democrats confirmed Monnes Anderson was the third hold-out.

On Wednesday, Monnes Anderson’s staff declined to comment.

Monnes Anderson’s donor base is far different than her other two colleagues. Her largest funders include labor unions and the Democratic Party. Her only donation from Boeing was $500 in 2009. She’s also accepted $1,000 from International Paper.