WASHINGTON (AP) — The Latest on Senate Republicans' tax overhaul bill (all times local):

8 p.m.

Senate Republicans may have hit a procedural snag in their bid to open Alaska's Arctic National Wildlife Refuge to oil drilling. An arcane budget rule may hinder GOP efforts to include drilling in the tax overhaul legislation.

Senate Democrats objected to the provision opening a portion of the remote refuge to oil drilling, saying measures to fast-track environmental approvals violate a rule designed to limit budget legislation to provisions that are mainly fiscal in nature. Congressional aides say the Senate parliamentarian has signaled agreement with Democrats, which could force Republicans to secure 60 votes for drilling, instead of 50 needed for the tax bill.

While the drilling measure's fate is unclear, stripping it from the tax bill would be a blow to Alaska Republican Lisa Murkowski, chair of the Senate energy panel and a key drilling proponent.

Republican aides say the problem is fixable, but environmental groups were celebrating Wednesday. Tiernan Sittenfeld of the League of Conservation Voters said the procedural hiccup "is what happens when you cut corners and try to sneak drilling into an already terrible tax bill."

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6:18 p.m.

The largest tax package in more than three decades has cleared a key procedural vote in the Senate as Republican lawmakers work to give President Donald Trump the biggest legislative victory of his first year in office.

The Senate voted 52-48 Wednesday to start debating the bill, which would provide generous tax cuts to businesses and more modest tax cuts to families and individuals. It was a party-line vote, with all Republicans in favor and all Democrats opposed.

Wednesday's vote paves the way for the Senate to potentially pass the bill later this week. Lawmakers would then try to reconcile it with a tax package passed by the House.

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4:20 p.m.

Conservative groups and lawmakers are lining up against a proposal by Senate Republicans to impose automatic tax increases on millions of Americans — if their sweeping tax package doesn't grow the economy and raise tax revenues as much as projected.

The opposition comes as the Senate starts debating the tax package. It could doom a delicately negotiated proposal aimed at mollifying deficit hawks who worry that tax cuts for businesses and individuals could add trillions to the nation's mounting national debt.

But tucking a potential tax increase into the tax cut bill isn't sitting well with conservatives.

Rep. Jeb Hensarling of Texas, calls the proposal "a uniquely bad idea."