Montana has updated its sexual assault laws this week to redefine consent, after decades of requiring victims to prove they had been forced to perform a sexual act by way of force or threats.

Governor Steve Bullock, Montana's Attorney General Tim Fox, and other legislators have signed six bills changing the definition of sexual assault — and reshaping the way court cases can be prosecuted.

Now, victims no longer need to prove that they were coerced by violence or threat to claim sexual assault. The bill also clarifies that the relationship a victim has with his or her abuser, and the way in which he or she is dressed, do not constitute consent.

Law: Attorney General Tim Fox (left), Senator Diane Sands (center) and Governor Steve Bullock (right) attended the signing of bills redefining sexual assault on Monday in Missoula

Governor Bullock signed two of these bills during a ceremony in Missoula on Monday night, including Senate Bill 29, which removes the requirement for survivors to show their attacker used forced against them.

The previous legislation, dating back to the 1970s, required prosecutors to prove the victim had been 'compelled to submit by force against the victim or another' to have the attacker convicted.

The new law accounts for the fact that someone can withdraw consent even if physical force or threats aren't used against them, and that coercing someone who has withdrawn consent to have sex is an assault.

'A person who knowingly has sexual intercoursewith another person without consent or with another person who is incapable of consent commits the offense of sexual intercourse without consent,' the bill reads.

In order to account for lack of consent, Senate Bill 29 proposes a definition of consent as 'words or overt actions indicating a freely given agreement to have sexual intercourse or sexual contact'.

It means that in absence of these clear indicators, someone cannot be considered to have given consent.

The new law further clarifies what does and does not constitute consent, and reads: 'an expression of lack of consent through words or conduct means there is no consent or that consent has been withdrawn.'

It also makes it clear that 'a current or previous dating or social or sexual relationship' or 'the manner of dress' do not constitute consent.

Thus, the new law acknowledges that sexual assault can occur between couples, friends, and people who have previously had consensual sex. It also makes it clear the victim's outfit should be left out of the equation.

The text also points out that in order to determine whether consent was given, it is necessary to look at the big picture. 'Lack of consent may be inferred based on all of the surrounding circumstances and must be considered in determining whether a person gave consent,' it reads.

Changes: Bullock (left) and other legislators have signed six bills changing the definition of sexual assault. Sands (right) sponsored Senate Bill 29, which removes the requirement for survivors to show their attacker used forced against them

Democratic Senator Diane Sands, who sponsored the bill and led the effort to draft it, pointed out that the previous rules were outdated and in many cases, left prosecutors powerless to pursue legal action against perpetrators.

'Most of these laws were passed in the 1970s when we had a very different idea of what sexual assault was. We have had many cases of a sexual assault that everyone agrees was a sexual assault [but] isn't a sexual assault under the law,' Sands told the Missoulian.

'We looked at really what it takes to convict someone of sexual assault. I'm very pleased we could actually pass these pieces of legislation, in most cases pretty much unanimously.'

The signing of the new bills came at the same time Montana took an important step in working through its backlog of sexual assault kits, left untested from past investigation.

A $2 million federal grant enabled the state to send out 1,140 backlogged kits this week. They will then be tested and investigated.

'We will soon be hiring a victim advocate and a cold case investigator, so we will be off and running on this process,' Fox told KGVO. 'In the meantime, we have developed policies and procedures and a database in order to track kits in the future so they don’t accumulate.'