U.S. Sen. Mazie Hirono isn’t up for election until 2018, but she continues to add more cash to her campaign coffers.

Hirono raised $111,352 from April 1 to June 30, according the latest reports filed with the Federal Election Commission.

She only spent $48,711 during the same time period, leaving her with $558,715 in cash on hand.

It’s likely Hirono will need a lot more cash in the coming years. Many political observers expect U.S. Rep. Tulsi Gabbard to challenge Hirono in 2018.

Gabbard’s war chest has a positive balance of $1,883,357, according to the latest data. It’s only expected to grow.

In fact, FEC filings show that from April 1 to June 30, Gabbard took in $420,917 in total receipts.

That’s second only to U.S. Sen. Brian Schatz, who has been the Hawaii delegation’s most prolific campaign fundraiser.

Gabbard hasn’t faced a serious challenger since she was first elected to Congress in 2012. That’s allowed her to sock away a lot of cash for a future run at higher office.

And just this weekend she made an odd plea for more money, saying in a campaign email that she was facing “multiple opponents who are twisting my record in an attempt to win voters. I need your help to defeat them.”