A look back at some of the biggest small business and start-up stories from the past week, with a focus on Washington.

The Senate is expected to pass a measure later this week that would give states more authority to charge sales tax on online transactions. (BECK DIEFENBACH/REUTERS)

Senate moving forward on online sales tax: In a preliminary vote last week, the Senate approved a measure that would give states much more authority to charge sales tax on online transactions. The bill is expected to formally pass in a final vote this week, but it faces an uphill battle in the House. If it passes into law, the measure could make life far more complicated for online retailers.

STEM scrutiny: A push to overhaul the immigration system has pushed the country’s supposed shortage of science and technology workers into the spotlight, as business leaders push lawmakers to ease some of the visa restrictions for highly skilled foreigners. However, new research suggests the U.S. is already churning out plenty of those workers to meet demand from the private sector.

Republicans shifting away from entitlement changes: Another budget battle looms this summer, and Republicans appear to be shifting their attention away from demands for entitlement cuts to focus instead on rewriting the tax code — a move that should prove popular among small business owners, according to recent polls.

SEC sends message with fraud suit: Criticized repeatedly for missing deadlines for new crowdfunding regulations, the Securties and Exchange Commission’s latest action against scammers serves as a reminder to restless entrepreneurs that the risks of opening the new financing portals are worth taking extra time to prevent.

Small firms still most vulnerable online: Small businesses continue to be the most common victims of cyberattacks, according to a study released last week by Verizon. Of the 621 confirmed data breaches the company recorded last year, nearly half hit firms with less than 1,000 employees and nearly a third hit those with less than 100 employees.

Love for small business isn’t universal:Six out of every seven Americans trust small businesses, according to a new poll by public relations firm Edelman, but that isn’t the case worldwide — in China, for instance, large firms (trusted by 89 percent) are held in higher esteem than small ones (trusted by 65 percent).

Open season for federal contracts:This summer could be a big one for small contractors, with more than $3 billion worth of work up for grabs and reserved for small business in the coming months. Moreover, this is the first year in which federal officials face potential penalties for not reaching their small business contracting goals.

OSB start-up of the week : Alcohoot: On a mission to deter drunk driving, the company has released an app-hardware combination that turns smartphones into police-grade breathalyzers.

What are you keeping an eye on this week? Please let us know below.