Tensions between the US and Russia touch a lot of fronts, including the 1987 Intermediate Nuclear Forces Treaty. The treaty forbids the development of intermediate range conventional and nuclear missiles, and there have been allegations one of the missiles tested by Russia is in violation of this treaty.
Russia has denied this is the case, but the House of Representatives appears uninterested in arguing the point, instead adding multiple lines to the nearly $700 billion military spending bill that was advanced in committee today, threatening to withdraw the US from the treaty, and funding US development of missiles that would deliberately violate it.
The US has little need of such missiles in the first place, as over the past three decades they’ve developed myriad alternative delivery systems that give them comparable capabilities to having intermediate ranged missiles, meaning the spending in the bill on this matter is wholly meant to spite Russia.
The putative Russian “violation” is related to a 2008 missile test they conducted. The US insisted it was a “possible violation” in 2014, and has never confirmed that this was the case, though Congress has repeatedly presented it as a fact.