By Corbett B. Daly and Thomas Ferraro WASHINGTON (Reuters) – A second senior Democratic lawmaker may face a public ethics trial this fall, adding a new threat to their party’s efforts to keep control of the House of Representatives in the November elections

* Obama urges Republicans to allow vote on bill * Reid hopeful that Senate can act on bill next week * Obama says he’ll call Republicans’ ‘bluff’ on deficit (Adds Obama comments on deficit in paragraphs 9-11) By Ross Colvin WASHINGTON, July 31 (Reuters) – U.S. President Barack Obama on Saturday accused Republicans of holding American small businesses “hostage to politics” after Republican senators refused to back a $30 billion small-business lending package.

DETROIT, July 31 (Reuters) – A U.S. congressional committee will probe the spill of more than 800,000 gallons (3 million litres) of oil from an Enbridge Inc (ENB.TO: Quote , Profile , Research ) pipeline in southern Michigan this week, a Michigan congressman said on Saturday

By Chris Allbritton and David Milliken ISLAMABAD/LONDON (Reuters) – Pakistan’s spy chief has canceled a trip to Britain, a spokesman said on Saturday, but Islamabad played down a row over remarks by British Prime Minister David Cameron suggesting Pakistan was not doing enough to fight terrorism. A spokesman for the Inter-Service Intelligence (ISI) agency said on Saturday that senior intelligence officials, including ISI head Lieutenant General Ahmad Shuja Pasha, would not go to London on Monday as planned for counter-terrorism talks. But President Asif Ali Zardari will still visit Britain next week, a government spokesman said.

* Grand jury hears testimony on disabled methane monitor * Explosion at mine killed 29 workers on April 5 CHICAGO, July 31 (Reuters) – A federal grand jury looking into an explosion that killed 29 workers at a Massey Energy Co (MEE.N: Quote , Profile , Research ) coal mine in West Virginia heard testimony this week about possible illegal tampering with a mine safety monitor, the Wall Street Journal reported on Saturday. The testimony addressed an incident in which an electrician allegedly disabled a methane monitor at the Upper Big Branch Mine, according to the report quoting people familiar with the matter. A former Massey worker who filed a whistle-blower lawsuit against the company reportedly witnessed the rewiring of a mining machine’s methane monitor, the article said citing his lawyer

LOS ANGELES, July 31 (Reuters) – Steve Carell’s new comedy “Dinner For Schmucks” took an early lead at the weekend box office in North America, according to preliminary estimates issued on Saturday, but faces a close race with reigning champ “Inception” for overall honors. “Schmucks” opened to $8.4 million on Friday, while “Inception” earned $8.15 million, said their respective distributors Paramount Pictures and Warner Bros Pictures. They are each on track to finish up in the low-$20 million range when estimates for the three-day period are issued on Sunday.

VIENNA (Reuters) – BP Plc is seeking to sell its German petrol station chain Aral for around 2 billion euros ($2.6 billion), German magazine Wirtschaftswoche reported on Saturday, citing investment bankers familiar with BP’s plans. BP last week unveiled plans to sell $30 billion of assets — mainly upstream oil and gas fields– over the next 18 months to cover costs related to the Gulf oil spill, the worst in U.S.