President-elect Donald Trump's agenda continues to unfold, but left-leaning states are making equally ambitious plans to fight against it.

Just as a number of states habitually blocked President Barack Obama's initiatives regarding overtime pay, the Affordable Care Act, and laws against "transgender bathroom bills," these states are planning to do the same, deploying a range of legal and constitutional methods at their disposal.

California is chief among the potential antagonists to Trump's potential lawmaking.

State lawmakers are already pondering a strategy similar to the one used by Texas to oppose President Obama: filing a lot of lawsuits. Officials in the state's Department of Justice are "analyzing how Trump may impact California in immigration, civil rights, health care, the environment, and consumer protections" and determining how to protect the state's progressive policies through litigation, the Los Angeles Times reported.

Several state attorneys general are also planning to act as a "first line of defense" against potential Trump policies that might be unconstitutional.

These elected officers have legal standing to sue the federal government in defense of state citizens. A number of federal courts are staffed with judges appointed by Obama, so Democratic attorneys general might have success using the justice system to fight rollbacks on climate change legislation, immigration rights, health care reform, and other areas Trump has pledged to change immediately.

Individual states might also serve as a bulwark against Trump in the area of abortion legislation.

Trump has vowed to nominate Supreme Court justices who will overturn Roe v. Wade, which would almost certainly send reproductive rights back to individual states to determine.

A number of states have standing abortion bans that would likely revert back to having legal standing.

But 15 other states have constitutional protections for abortion rights, no matter what happens at the federal level. These states could serve as a refuge for women in need, should the scenario of a Roe overturn come to pass.

Fighting the Trump administration can also happen at the city level.

A number of mayors of major cities have already vowed to protect their citizens against mass deportations — even at the risk of loss of federal funding.

New York's Mayor Bill de Blasio, Chicago's Rahm Emanuel, Los Angeles' Eric Garcetti, and Seattle's Ed Murray have all publicly vowed not to enforce orders to begin large-scale roundups of undocumented immigrants.

De Blasio, in particular, occupies a special position in the organized resistance of a Trump agenda: New York is essentially the president-elect's home base. Trump has rarely left Trump Tower since his election, forcing the NYPD and Secret Service to enact an ad hoc plan to secure the building and protect the president-elect's family.

The mayor recently announced that he would seek reimbursement from the federal government for the considerable costs of protecting the president-elect and that he would keep the heavily trafficked stretch of Fifth Avenue in front of the building open, despite the potential security problems it might create.

As President-elect Trump continues to unveil his agenda, expect more resistance from progressive states and cities, setting the stage for the same kind of gridlock President Obama faced during his time in office.