Two of Sen. Sinema's former aides have recently lobbied for corporate giants looking to influence Biden's agenda

The two people, Kate Gonzales and Alyssa Marois, appear to be rare examples of former Sinema staffers registered to lobby the federal government. Their position makes them particularly valuable to their clients since their former boss, an Arizona Democrat, is a pivotal vote in a Senate split 50-50 by party.

Sinema and conservative Democratic Sen. Joe Manchin, D-W.V., have played a vital role in the Democratic-held Senate in the past year as their party tries to pass bills including Biden's Build Back Better Act with a simple majority. A single Democratic defection can sink major legislation.

Sinema has not committed to voting for the Build Back Better Act, Biden's $1.75 trillion social and climate spending package. As Democrats negotiated the Build Back Better Act last year, Sinema shot down Biden's proposal to raise the corporate tax rate to at least 25% from 21%. She backed more complicated plans for a minimum corporate tax and a surtax on the wealthiest individuals.

The centrist has also rankled members of her party on other issues: while she supports an elections reform bill the Senate plans to take up this week, she has opposed eliminating the filibuster to pass the controversial bill in the face of unified Republican efforts to block it.

Sinema helped to write and voted for Biden's recently signed $1 trillion infrastructure law. For his part, Manchin has opposed the Build Back Better plan and making any changes to filibuster rules.

Gonzales, one of the former Sinema aides turned lobbyists, must wait a year before being able to lobby Sinema's office, according to Senate rules. Gonzales' LinkedIn page says she left Sinema's office in April after five months as a policy advisor.

Her previous experience includes just over a year as a legislative aide for Sinema. Gonzales could still lobby other lawmakers and their staffs.

Representatives for HSBC and Sinema's office declined to comment. Gonzales, Marois and the other current clients mentioned in this story did not return requests for comment before publication.

Marois, who worked for Sinema's office while she was in the House of Representatives, became the senior vice president of public affairs at HSBC last year. The company announced her hiring in late September. She was previously a lobbyist for Wall Street titan J.P. Morgan Chase.

A third-quarter lobbying disclosure report, which covers July through September, shows that Marois helped to lobby for HSBC on bills in which Sinema has played a major role. The report lists the House-passed Build Back Better Act, the American Rescue Plan signed last year and the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) passed in 2020.

Sinema voted for the latter two bills and has not committed to supporting the House version of Build Back Better.

The lobbying report notes that Marois and the lobbying team at HSBC engaged with the House, Senate, the Federal Reserve, the Federal Deposit Insurance Corporation and the Office of the Comptroller of the Currency.

Marois was a legislative director for Sinema for part of 2017, according to the nonpartisan Center for Responsive Politics. Sinema won election to the Senate in 2018.

Many former advisors to lawmakers end up becoming lobbyists. A group of ex-aides to Manchin have recently gained influential clients including gas and oil giant Hess, media juggernaut Comcast and a nonprofit founded by a former campaign manager for Mike Bloomberg.

Gonzales held various roles with Sinema and had a stint with Biden's presidential campaign before she became a policy advisor at lobbying juggernaut Brownstein Hyatt Farber Schreck in April, according to her LinkedIn profile.

Gonzales' profile on her firm's website says she is part of the lobbying shop's energy, environment and resource strategies group. The website notes that Gonzales "provides clients insight into Democratic priorities and fresh intelligence on where and when policy is likely to move. She is highly skilled at developing compelling messaging for moderate Democrats and Republicans, critical voting blocks in a narrowly divided Congress."

Mining company Broken Hill Proprietary and investment firm C5 Capital are among her recent clients, according to lobbying registration. BHP has a presence in Texas and is headquartered in Australia. Gonzales and one of her other colleagues at Brownstein registered to lobby for BHP in December on "issues related to legacy mining assets," the form says.

C5 Capital, which has offices in London, New York and Luxembourg, says Gonzales and other lobbyists at the firm are working on "issues related to nuclear energy." They registered to lobby for the investment firm in November.

A third-quarter lobbying report shows Gonzales and her colleagues lobbied for Starbucks on "issues related to ethical sourcing, sustainability, and green buildings." They targeted the House, Senate, the Environmental Protection Agency and the Department of Energy, according to the filing.

Power company Duke Energy saw Gonzales and fellow Brownstein lobbyists engage with the House, Senate and Department of Energy in the third quarter on issues tied to Build Back Better and "clean air regulations and legislation and climate change, natural gas, renewables, and other aspects of energy policy," according to the report.