People cast their ballots at a community center during early voting October 25, 2018 in Potomac, Maryland, two weeks ahead of the key US midterm polls. ( Brendan Smialowski | AFP | Getty Images

Voters across the country will head to the polls on Tuesday to determine which party controls the House of Representatives and the Senate for the final two years of President Donald Trump's first term in office. But it is not just lawmakers on the ballot. More than 150 ballot measures will be up for consideration on Tuesday, according to a Ballotpedia tally, including 63 measures placed on the ballot by petition that could create new laws or strike down old ones, circumventing state legislatures. The bottom of the ballot may not be earning headlines, but it is fertile ground for big spenders looking to shape policy at the state level. Ballot measure campaigns have spent more than $1 billion this cycle — on par with the amount raised for a successful presidential bid — and have attracted the attention of major businesses and spending groups. The issues are heavily charged. In three states, West Virginia, Oregon and Alabama, voters will consider placing new limits on abortion access. In three others — Idaho, Utah and Nebraska — voters could choose to expand Medicaid over strong local Republican opposition. The key issues this year are election reform and marijuana legalization, with voters in 16 states taking up the issues. Measures in a number of states have pit renewable energy proponents against heavily funded opposition campaigns. Six states could face tougher limits on their ability to collect taxes.

Election reform

One of the most closely watched initiatives is a Florida proposal that could restore voting rights to most convicted felons in the state. The measure is expected to pass, which would enfranchise more than 1.5 million people — 10 percent of the voting population — in a state that often proves critical in presidential races. Interestingly, there has been little in the way of organized opposition. Voters in four other states will decide issues that observers say could "end gerrymandering" by shifting redistricting decisions from elected officials to independent commissions. It's an issue that has rattled statehouses around the country and could prove consequential for the national political landscape. The U.S. Supreme Court took up the issue earlier this year, but ultimately punted on a major ruling, lending more weight to the measures on the ballot in Michigan, Utah, Missouri and Colorado.

Marijuana legalization

Despite a federal prohibition, nine states and the District of Columbia allow for recreational marijuana use. If pot advocates have their way on Tuesday, two more states could join in. Voters in Michigan and North Dakota will decide whether to permit recreational weed use via ballot measures this Election Day. That is in addition to measures in Missouri and Utah that could allow the drug for medicinal purposes. 2016 was seen as a watershed year for marijuana legalization, and much of the activity took place via ballot measure. Arkansas, California, Florida, Massachusetts, Nevada and North Dakota all increased access to marijuana that year.

Renewable energy