– Field organizers working for Minnesota U.S. Sen. Amy Klobuchar’s presidential campaign will soon qualify for union cards, a rising trend in Democratic politics.

Klobuchar’s campaign announced that a group of field organizers has designated Iowa-based Teamsters Local 238 as its bargaining representative for organizers on the campaign, and that the union and campaign would negotiate a collective bargaining agreement.

“Amy and our campaign are pro-union and we support organized labor,” Justin Buoen, Klobuchar’s campaign manager, said in a statement. Buoen noted that she is the daughter and granddaughter of union members, something she frequently campaigns on.

Although political campaigns can be fluid, short-term affairs, Democratic candidates making bids for the White House and congressional offices have seen an uptick in union organizing within their own ranks. It’s both an affirmation and a test of the party’s affinity for organized labor, an important part of the Democratic coalition.

Field organizers on former Vice President Joe Biden’s presidential campaign also joined Teamsters Local 238 last Friday, and South Bend, Ind., Mayor Pete Buttigieg’s organizers are joining a Massachusetts-based union. Workers for the campaigns of Sens. Elizabeth Warren and Bernie Sanders organized earlier this year, and workers for other candidates including Sen. Cory Booker and U.S. Rep. Julian Castro have also moved to do so.

The recent announcements by the Biden, Buttigieg and Klobuchar campaigns come ahead of an important labor event this upcoming weekend in Iowa, whose first-in-the-nation presidential caucus comes on Feb. 3. On Saturday, the Teamsters are hosting a workers forum for presidential candidates in Cedar Rapids, with Klobuchar, Biden, Buttigieg, Sanders and others all scheduled to participate.

U.S. Sen. Klobuchar is the daughter and granddaughter of union members.

“Political campaign workers deserve a voice on the job as much as anyone,” International Brotherhood of Teamsters President James P. Hoffa told Bloomberg News. He said campaign workers “face the prospect of long, pressure-filled hours on the campaign trail.”

The Klobuchar campaign did not reveal Monday how many of its employees would be covered in the bargaining unit or how many people work for the campaign, but said the unit will cover nonmanagerial field staff.

Field organizers make a minimum of $42,000 a year, according to a campaign spokeswoman. All employees receive health coverage and paid time off, she said. Klobuchar has publicly said that she supports a federal minimum wage increase to $15 an hour.

Field organizers are typically young campaign workers who help with voter outreach efforts, event planning and execution in a set geographic area.

Paying union-scale wages and benefits could increase the Klobuchar campaign’s operating costs as she battles to raise money and close the gap with the top tier candidates in the Democratic primary contest.

Sanders was the first presidential campaign to see a group of employees organize, and the Vermont senator announced in a CNN interview in June that his campaign had reached a deal with the United Food and Commercial Workers Local 400 that would ensure all field organizers earned a minimum salary equivalent to at least $15 an hour.

A burst of union organizing among Democratic House campaigns in 2018 helped pave the way for the efforts to hit presidential campaigns this year. In March 2018, the campaign of Erin Murphy, a Democratic candidate for governor of Minnesota, became the first unionized gubernatorial campaign in the country. Later in the year, workers at the Minnesota Democratic-Farmer-Labor Party also formed a union.

“We frequently move across the country for candidates we believe in,” reads the website of the Campaign Workers Guild, which has helped drive the organizing efforts at various Democratic campaigns. “Too often, we work over 80 hours a week for less than minimum wage. We routinely pay for office supplies, gas, and basic campaign materials out of our own pockets without a clear reimbursement policy. And too many of us put up with sexual harassment because we don’t have a way to report it and get help.”

Democratic and Republican campaigns alike hire field organizers, but given some Republicans’ antipathy toward organized labor, analysts consider it unlikely that Republican campaigns will see union drives in 2020.