The 1996 Congressional Review Act (CRA) can overturn "midnight rules" created by an outgoing president. Until President Trump assumed office, it was successfully used only once. Trump has used it 14 times.

Between the lines: The CRA says that once a rule is killed, the executive branch can never come back with a rule that is "substantially the same form." When Democrats controlled Washington from 2009-2010, they avoided using the CRA, opting instead to re-regulate any unfavored Bush-era rules.

Why it matters: The fast-track tactic to reverse Obama's legacy fulfills Trump's campaign promises, but is also a blunt approach to gain political points. The divide between right and left is intensifying, as Democrats see the CRA as an abuse of power to appease the far right and special interests.

The overturned regulations:

1. Federal Contractor blacklisting rule, which required companies to report any law violation from the last three years when bidding on federal contracts over $500,000. (Feb. 1)
2. The Stream Buffer rule, which restricted coal companies from dumping waste into streams. (Feb. 2)
3. Bureau of Land Management venting and flaring rule, which reduced air pollution from methane. (Feb. 2)
4. Social Security Service's Second Amendment restrictions, which added additional mental health background to gun sales. (Feb. 2)
5. SEC's resource extraction rule, which required oil and gas companies to disclose foreign payments. (Feb. 3)
6. Bureau of Land Management planning 2.0 rule, which gave the public greater control over in natural resource and land use planning. (Feb. 6)
7. The teacher preparation rule, which required states to issue annual ratings for teacher-prep programs. (Feb. 7)
8. The education accountability rule, which required states to evaluate their schools and holds them accountable for students performance. (Feb. 7)
9. The state retirement plan rule, which encouraged state governments to offer retirement savings plans for private-sector workers. (Feb. 15)
10. The local retirement plan rule, which exempted local municipal retirement savings plans from strict pension protection laws. (Feb. 15)
11. The national wildlife hunting and fishing rule, which banned predator hunting not approved by the federal government on national wildlife refuges. (Feb. 16)
12. The unemployment insurance drug testing rule, which limited drug testing for unemployment benefits. (March 14)
13. FCC internet privacy rules, which would have required companies get their customers' permission before sharing their data with advertisers. (April 3)
14. Title X abortion funding rule, which restricted states from withholding federal funding to Planned Parenthood and groups that provide abortion services. (April 13)